MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2

Question 1.
Find the area of each of the following parallelograms:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 1
Solution:
Area of parallelogram = Base × Height
(a) Height = 4 cm, Base = 7 cm
Area of parallelogram = 7 × 4 = 28 cm2

(b) Height = 3 cm, Base = 5 cm
Area of parallelogram = 5 × 3 = 15 cm2

(c) Height = 3.5 cm, Base = 2.5 cm
Area of parallelogram = 2.5 × 3.5 = 8.75 cm2

(d) Height = 4.8 cm, Base = 5 cm
Area of parallelogram = 5 × 4.8 = 24 cm2

(e) Height = 4.4 cm, Base = 2 cm
Area of parallelogram = 2 × 4.4 = 8.8 cm2

Question 2.
Find the area of each of the following triangles:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 2
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 3
Solution:
Area of triangle = \(\frac{1}{2}\) × Base × Height
(a) Base = 4 cm, height = 3 cm
Area = \(\frac{1}{2}\) × 4 × 3 = 6 cm2

(b) Base = 5 cm, height = 3.2 cm
Area = \(\frac{1}{2}\) × 5 × 3.2 = 8 cm2

(c) Base = 3 cm, height = 4 cm
Area = \(\frac{1}{2}\) × 3 × 4 = 6cm2

(d) Base = 3 cm, height = 2 cm
Area = \(\frac{1}{2}\) × 3 × 2 = 3 cm2

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2

Question 3.
Find the missing values:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 4
Solution:
Area of parallelogram = Base × Height
(a) Base = 20 cm
Let height = h
Area of parallelogram = 246 cm2
∴ 20 × h = 246
⇒ h = \(\frac{246}{20}\) = 12.3 cm
Therefore, the height of parallelogram is 12.3 cm.

(b) Let base = b
Height = 15 cm
Area of parallelogram = 154.5 cm2
∴ b × 15 = 154.5
⇒ b = \(\frac{154.5}{15}\) = 10.3 cm
Therefore, the base of parallelogram is 10.3 cm.

(c) Let base = b
Height = 8.4 cm
Area of parallelogram = 48.72 cm2
∴ b × 8.4 = 48.72
⇒ b = \(\frac{48.72}{8.4}\) = 5.8 cm
Therefore, the base of parallelogram is 5.8 cm.

(d) Base = 15.6 cm
Let height = h
Area of parallelogram = 16.38 cm2
∴15.6 × h = 16.38
⇒ h = \(\frac{16.38}{15.6}\) = 1.05 cm
Therefore, the height of parallelogram is 1.05 cm.

Question 4.
Find the missing values:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 5
Solution:
Area of triangle = \(\frac{1}{2}\) × Base × Height
Let b be the base of triangle and h be the height of triangle.
(i) b = 15 cm
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 6
Therefore, the height of triangle is 11.6 cm.

(ii) h = 31.4 mm
Area = \(\frac{1}{2}\) × b × h = 1256 mm2
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 7
Therefore, the base of triangle is 80 mm.

(iii) b = 22 cm
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 8
Therefore, the height of triangle is 15.5 cm.

Question 5.
PQRS is a parallelogram (see the given figure). QM is the height from Q to SR and QN is the height from Q to PS. If SR = 12 cm and QM = 7.6 cm. Find:
(a) the area of the parallelogram PQRS
(b) QN, if PS = 8 cm
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 9
Solution:
(a) Area of parallelogram = Base × Height
= SR × QM
= 12 × 7.6 = 91.2 cm2

(b) PS = 8 cm
Area of parallelogram = Base × Height
= PS × QN = 91.2 cm2
⇒ 8 × QN = 91.2
⇒ QN = \(\frac{91.2}{8}\) = 11.4 cm

Question 6.
DL and BM are the heights on sides AB and AD respectively of parallelogram ABCD (see the given figure).
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 10
If the area of the parallelogram is 1470 cm2, AB = 35 cm and AD = 49 cm, find the length of BM and DL.
Solution:
Area of parallelogram = Base × Height
= AB × DL
⇒ 1470 = 35 × DL
⇒ DL = \(\frac{1470}{35}\) = 42 cm
Also, area of parallelogram = AD × BM
⇒ 1470 = 49 × BM
∴ BM = \(\frac{1470}{49}\) = 30 cm

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2

Question 7.
∆ABC is right angled at A (see the given figure). AD is perpendicular to BC. If AB = 5 cm, BC – 13 cm and AC = 12 cm, find the area of ∆ABC. Also find the length of AD.
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 11
Solution:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 12

Question 8.
∆ABC is isosceles with AB = AC= 7.5 cm and BC = 9 cm (see the given figure). The height AD from A to BC, is 6 cm. Find the area of ∆ABC. What will be the height from C to AB i. e., CE?
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 13
Solution:
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.2 14

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2

Question 1.
Convert the given fractional numbers to percents.
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 1
Solution:
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 2

Question 2.
Convert the given decimal fractions to percents.
(a) 0.65
(b) 2.1
(c) 0.02
(d) 12.35
Solution:
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 14

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2

Question 3.
Estimate what part of the figures is coloured and hence find the percent which is coloured.
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 4
Solution:
(i) Here, 1 part out of 4 equals parts is shaded which represents the fraction \(\frac{1}{4}\).
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 5

(ii) Here, 3 parts out of 5 equal parts are shaded which represents the fraction \(\frac{3}{5}\).
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 6

(iii) Here 3 parts out of 8 equal parts are shaded which represents the fraction \(\frac{3}{8}\).
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 7

Question 4.
Find:
(a) 15% of 250
(b) 1% of 1 hour
(c) 20% of ₹ 2500
(d) 75% of 1 kg
Solution:
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 8

Question 5.
Find the whole quantity if
(a) 5% of it is 600
(b) 12% of it is? 1080
(c) 40% of it is 500 km
(d) 70% of it is 14 minutes
(e) 8% of it is 40 litres
Solution:
Let the whole quantity be x.
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 9
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 10

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2

Question 6.
Convert given percents to decimal fractions and also to fractions in simplest forms:
(a) 25%
(b) 150%
(c) 20%
(d) 5%
Solution:
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 11

Question 7.
In a city, 30% are females, 40% are males and remaining are children. What percent are children?
Solution:
It is given that 30% are females and 40% are males.
Children = 100% – (40% + 30%)
= 100% – 70% = 30%

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2

Question 8.
Out of 15,000 voters in a constituency, 60% voted. Find the percentage of voters who did not vote. Can you now find how many actually did not vote?
Solution:
Percentage of voters who voted = 60%
Percentage of those who did not vote = 100% – 60%
= 40%
Number of people who did not vote = 40% of 15000
= 40% × 15000
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 12
Therefore, 6000 people did not vote.

Question 9.
Meeta saves ₹ 400 from her salary. If this is 10% of her salary. What is her salary?
Solution:
Let Meeta’s salary be ₹ x.
Given that, 10% of x = 400
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.2 13
Therefore, Meeta’s salary is ₹ 4000.

Question 10.
A local cricket team played 20 matches in one season. It won 25% of them. How many matches did they win?
Solution:
Number of games won = 25% of 20
\(=\frac{25}{100} \times 20=5\)
Therefore, the team won 5 matches.

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.1

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.1

Question 1.
The length and the breadth of a rectangular piece of land are 500 m and 300 m respectively. Find
(i) its area
(ii) the cost of the land, if 1 m2 of the land costs ₹ 10,000.
Solution:
Length (l) = 500 m
Breadth (b) = 300 m
(i) Area = Length × Breadth = 500 × 300 = 150000 m2
(ii) Cost of 1 m2 land = ₹ 10000
∴ Cost of 150000 m2 land
= 150000 × 10000 = ₹ 1500000000

Question 2.
Find the area of a square park whose perimeter is 320 m.
Solution:
Perimeter of the square park = 320 m
∴ 4 × Length of the side of park = 320
Length of the side of park = \(\frac{320}{4}\) = 80 m
Area = (Length of the side of park)2
= (80)2 = 6400 m2

Question 3.
Find the breadth of a rectangular plot of land, if its area is 440 m2 and the length is 22 m. Also find its perimeter.
Solution:
Area of a rectangular plot = 440 m2
Length = 22 m
Area = Length x Breadth = 440 m2
∴ 22 × Breadth = 440
⇒ Breadth = \(\frac{440}{22}\) = 20 m
∴ Perimeter = 2 (Length + Breadth)
= 2 (22 + 20) = 2(42) = 84 m

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.1

Question 4.
The perimeter of a rectangular sheet is 100 cm. If the length is 35 cm, find its breadth. Also find the area.
Solution:
Length = 35 cm
Perimeter = 100 cm
∴ 2 (35 + Breadth) = 100
⇒ 35 + Breadth = 50
⇒ Breadth = 50 – 35 = 15 cm
∴ Area = Length × Breadth
= 35 × 15 = 525 cm2

Question 5.
The area of a square park is the same as of a rectangular park. If the side of the square park is 60 m and the length of the rectangular park is 90 m, find the breadth of the rectangular park.
Solution:
Side of the square park = 60 m
Length of the rectangular park = 90 m
Area of the square park = (side)2 = (60)2 = 3600 m2
Area of rectangular park = Length × Breadth
= 90 × Breadth
It is given that area of square park = area of rectangular park
∴ 3600 = 90 × Breadth
⇒ Breadth = 40 m

Question 6.
A wire is in the shape of a rectangle. Its length is 40 cm and breadth is 22 cm. If the same wire is rebent in the shape of a square, what will be the measure of each side. Also find which shape encloses more area?
Solution:
Length of rectangle = 40 cm
Breadth of rectangle = 22 cm
Perimeter of rectangle = Perimeter of square
∴ 2 (Length + Breadth) = 4 × Side of square
⇒ 2 (40 + 22) = 4 × Side of square
⇒ 2 × 62 = 4 × Side of square
∴ Side of square = \(\frac{124}{4}\) = 31 cm
Now, area of rectangle = 40 × 22 = 880 cm2
Area of square = (Side)2 = 31 × 31 = 961 cm2
As 961 > 880.
Therefore, the square-shaped wire encloses more area than rectangle – shaped wire.

MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.1

Question 7.
The perimeter of a rectangle is 130 cm. If the breadth of the rectangle is 30 cm, find its length. Also find the area of the rectangle.
Solution:
Breadth = 30 cm
Perimeter = 130 cm
∴ 2 (Length + 30) = 130
⇒ Length + 30 = 65
⇒ Length = 65 – 30 = 35 cm
Now, area = Length × Breadth
= 35 × 30 = 1050 cm2

Question 8.
A door of length 2 m and breadth 1 m is fitted in a wall. The length of the wall is 4.5 m and the breadth is 3.6 m (see the given figure). Find the cost of white washing the wall, if the rate of white washing the wall is ₹ 20 per m2.
MP Board Class 7th Maths Solutions Chapter 11 Perimeter and Area Ex 11.1 1
Solution:
Length of wall = 4.5 m
Breadth of wall = 3.6 m
Area of wall = Length × Breadth
= 4.5 × 3.6
= 16.2 m2
Area of door = 2 × 1 = 2 m2
Area to be white-washed
= Area of wall – Area of door
= 16.2 – 2 = 14.2 m2
Cost of white-washing 1 m2 area = ₹ 20 2.
∴ Cost of white-washing 14.2 m2 area
= 14.2 × 20 = ₹ 284

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4

Question 1.
Observe the patterns of digits made from line segments of equal length. You will find such segmented digits on the display of electronic
watches or calculators,
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 1
If the number of digits formed is taken to be n, the number of segments required to form n digits is given by the algebraic expression appearing on the right of each pattern. How many segments are required to form 5, 10, 100 digits of the kind
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 2
Solution:
(a) It is given that the number of segments required to form n digits of the kind
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 3 is (5n + 1).
Number of segments required to form 5 digits = (5 × 5 + 1) = 25 + 1 = 26
Number of segments required to form 10 digits = (5 × 10 + 1) = 50 + 1 = 51
Number of segments required to form 100 digits = (5 × 100 + 1) = 500 + 1 = 501

(b) It is given that the number of segments required to form n digits of the kind
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 4 [ is (3n +1).
Number of segments required to form 5 digits = (3 × 5 + 1) = 15 + 1 = 16
Number of segments required to form 10 digits = (3 × 10 + 1) = 30 + 1 = 31
Number of segments required to form 100 digits = (3 × 100 + 1) = 300 + 1 = 301

(c) It is given that the number of segments required to form n digits of the kind
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 5 is (5n + 2).
Number of segments required to form 5 digits = (5 × 5 + 2) = 25 + 2 = 27
Number of segments required to form 10 digits = (5 × 10 + 2) = 50 + 2 = 52
Number of segments required to form 100 digits = (5 × 100 + 2) = 500 + 2 = 502

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4

Question 2.
Use the given algebraic expression to complete the table of number patterns.
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 6
Solution:
(i) Number pattern for expression 2n – 1
Put n = 1, 2, 3,…. and so on, we get
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.4 7
(ii) For expression 3 n + 2, 5th, 10th term and 100th term of the pattern are 3 × 5 + 2 = 17, 3 × 10 + 2 = 32 and 3 × 100 + 2 = 302 respectively.
(iii) For expression 4n +1, 5th, 10th and 100th term of the pattern are 4 × 5 +1 = 21, 4 × 10 + 1 = 41 and 4 × 100 + 1 = 401 respectively.
(iv) For expression 7n + 20, 5th, 10th and 100th term of the pattern are 7 × 5 + 1 = 36, 7 × 10 + 20 = 90 and 7 × 100 + 20 = 720 respectively.
(v) For expression n2 + 1, 5th and 10th term of the pattern are 52 + 1 = 26 and 102 + 1 = 101 respectively.

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1

Question 1.
Find the ratio of:
(a) ₹ 5 to 50paise
(b) 15 kg to 210 g
(c) 9 m to 27 cm
(d) 30 days to 36 hours
Solution:
(a) ₹ 5 to 50 paise
1 rupee = 100 paise
∴ 5 rupee = 500 paise
Hence, the required ratio is
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1 1

(b) 15 kg to 210 g
1kg = 1000g
15 kg = 15000 g
Hence, the required ratio is
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1 2

(c) 9 m to 27 cm
1m = 100 cm
9 m = 900 cm
Hence, the required ratio is
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1 3

(d) 30 days to 36 hours
1 day = 24 hours
30 days = 24 × 30 = 720 hrs
Hence, the required ratio is
MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1 4

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1

Question 2.
In a computer lab, there are 3 computers for every 6 students. How many computers will
be needed for 24 students?
Solution:
For 6 students, number of computers required = 3
For 1 student, number of computers required = \(\frac{3}{6}\)
For 24 students, number of computers required = \(24 \times \frac{3}{6}=12\)
Hence, 12 computers are required for 24 students.

Question 3.
Population of Rajasthan = 570 lakhs and population of UP = 1660 lakhs.
Area of Rajasthan = 3 lakhs km2 and Area of UP = 2 lakhs km2
(i) How many people are there per km2 in both these states ?
(ii) Which states is less populated?
Solution:
(i) Population of Rajasthan in 3 lakhs km2
area = 570 lakhs
Population of rajasthan in 1 km2 area
\(=\frac{570}{3}=190\) lakhs
Population of U.P. in 2 km2 = 1660 lakhs
Population of U.P. in 1 km2 = \(\frac{1660}{2}\)
= 830 lakhs

(ii) It can be observed that population per km2 area is lesser for Rajasthan. Therefore, Rajasthan is less populated.

MP Board Class 7th Maths Solutions Chapter 8 Comparing Quantities Ex 8.1

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.3

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.3

Question 1.
If m = 2, find the value of:
(i) m – 2
(ii) 3m – 5
(iii) 9 – 5m
(iv) 3m2 – 2m – 7
(v) \(\frac{5 m}{2}\) – 4
Solution:
(i) m – 2 = 2 – 2 = 0
(ii) 3m – 5 = (3 × 2) – 5 = 6 – 5 = 1
(iii) 9 – 5m = 9 – (5 × 2) = 9 – 10 = -1
(iv) 3m2 – 2m – 7 = 3 × (2 × 2) – (2 × 2) – 7
= 12 – 4 – 7 = 1
(v) \(\frac{5 m}{2}\) – 4 = \(\left(\frac{5 \times 2}{2}\right)\) – 4 = 5 – 4 = 1

Question 2.
If p = -2, find the value of:
(i) 4p + 7
(ii) -3p2 + 4p + 7
(iii) -2p3 – 3p2 + 4p + 7
Solution:
(i) 4p + 7 = 4 × (-2) + 7 = -8 + 7 = -1
(ii) -3p2 + 4p + 7 = -3 × (-2) × (-2) + 4 × (-2) + 7 = -12 – 8 + 7 = -13
(iii) -2p3 – 3p2 + 4p + 7
= -2 × (-2) × (-2) × (-2) – 3 × (-2) × (-2) + 4 × (-2) + 7
= 16 – 12 – 8 + 7 = 3

Question 3.
Find the value of the following expressions, when x = -1:
(i) 2x – 7
(ii) -x + 2
(iii) x2 + 2x + 1
(iv) 2x2 – x – 2
Solution:
(i) 2x – 7 = 2 × (-1) – 7 = -2 – 7 = -9
(ii) – x + 2 = – (-1) + 2 = 1 + 2 = 3
(iii) x2 + 2x + 1 = (-1) × (-1) + 2 × (-1) + 1 = 1 – 2 + 1 = 0
(iv) 2x2 – x – 2 = 2 × (-1) × (-1) – (-1) – 2 = 2 + 1 – 2 = 1

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.3

Question 4.
If a = 2, b = -2, find the value of:
(i) a2 + b2
(ii) a2 + ab + b2
(iii) a2 – b2
Solution:
(i) a2 + b2 = 2 × 2 + (-2) × (-2) = 4 + 4 = 8
(ii) a2 + ab + b2 = (2 × 2) + 2 × (-2) + (-2) × (-2) = 4 – 4 + 4 = 4
(iii) a2 – b2 = 2 × 2 – (-2) × (-2) = 4 – 4 = 0

Question 5.
When a = 0, b = -1, find the value of the given expressions:
(i) 2a + 2b
(ii) 2a2 + b2 + 1
(iii) 2a2b + 2ab2 + ab
(iv) a2 + ab + 2
Solution:
(i) 2a + 2b = 2 × (0) + 2 × (-1) = 0 – 2 = – 2
(ii) 2a2 + b2 + 1 = 2 × (0) × (0) + (-1) × (-1) + 1 = 0 + 1 + 1 = 2
(iii) 2a2b + 2ab2 + ab = 2 × (0) × (0) × (-1) + 2 × (0) × (-1) × (-1) + 0 × (-1)
= 0 + 0 + 0 = 0
(iv) a2 + ab + 2 = (0) × (0) + 0 × (-1) + 2
= 0 + 0 + 2 = 2

Question 6.
Simplify the expressions and find the value, if x is equal to 2.
(i) x + 7 + 4 (x – 5)
(ii) 3(x + 2) + 5x – 7
(iii) 6x + 5(x – 2)
(iv) 4(2x – 1) + 3x+ 11
Solution:
(i) x + 7 + 4(x – 5) = x + 7 + 4x – 20
= (1 + 4)x + (7 – 20) = 5x – 13
Putting x = 2 we get,
5x – 13 = (5 × 2) – 13 = 10 – 13 = -3

(ii) 3 (x + 2) + 5x – 7 = 3x + 6 + 5x – 7
= (3 + 5)x + (6 – 7) = 8x – 1
Putting x = 2 we get,
8x – 1 = (8 × 2) – 1 = 16 – 1 = 15

(iii) 6x + 5(x – 2) = 6x + 5x – 10
= (6 + 5)x – 10 = (11x – 10)
Putting x = 2 we get,
11x – 10 = (11 × 2) – 10 = 22 – 10 = 12

(iv) 4(2x – 1) + 3x + 11 = 8x – 4 + 3x + 11
= (8 + 3) × + (11 – 4) = 11x + 7
Putting x = 2 we get,
11x + 7= (11 × 2) + 7 = 22 + 7 = 29

Question 7.
Simplify these expressions and find their values if x = 3, a = -1, b = -2.
(i) 3x – 5 – x + 9
(ii) 2 – 8x + 4x + 4
(iii) 3a + 5 – 8o + 1
(iv) 10 – 3b – 4 – 5b
(v) 2a – 2b – 4 – 5 + a
Solution:
(i) 3x – 5 – x + 9 = (3 – 1) x + (-5 + 9)
= 2x + 4 = (2 × 3) + 4 [∵ x = 3]
= 6 + 4 = 10

(ii) 2 – 8x + 4x + 4 = 2 + 4 + (- 8 + 4)x
= 6 – 4x = 6 – (4 × 3) = 6 – 12 = -6 [∵ x = 3]

(iii) 3a + 5 – 8a +1 = (3 – 8)a + (5 + 1)
= -5a + 6
= -5 × (-1) + 6     [∵ a = -1]
= 5 + 6 = 11

(iv) 10 – 3b – 4 – 5b = 10 – 4 + (- 3 – 5)b
= 6 – 8b = 6 – 8 × (-2) [∵ b = -2]
= 6 + 16 = 22

(v) 2a – 2b – 4 – 5 + a = (2 + 1)a – 2b – 4 – 5
= 3a – 2b – 9
= 3 × (-1) – 2 × (-2) – 9 [∵ a = -1, b = -2]
= -3 + 4 – 9 = -8

Question 8.
(i) If z = 10, find the value of z3 – 3(z – 10).
(ii) If p = -10, find the value of p2 – 2p -100.
Solution:
(i) For z = 10,
z3 – 3z + 30
= (10 × 10 × 10) – (3 × 10) + 30
= 1000 – 30 + 30 = 1000

(ii) For p = -10,
p2 – 2p – 100
=(-10) × (-10) – 2 × (-10) – 100
= 100 + 20 – 100 = 20

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.3

Question 9.
What should be the value of a if the value of 2x2 + x – a equals to 5, when x = 0?
Solution:
When x = 0; 2x2 + x – a = 5,
∴ (2 × 0) + 0 – a = 5
⇒ 0 – a = 5
⇒ a = -5

Question 10.
Simplify the expression and find its value when a = 5 and b = -3.
2(a2 + ab) + 3 – ab
Solution:
2(a2 + ab) + 3 – ab = 2a2 + 2ab + 3 – ab
= 2a2 + (2 – 1) ab + 3 = 2a2 + ab + 3
= 2 × (5 × 5) + 5 × (-3) + 3       [ ∵ a = 5, b = – 3]
= 50 – 15 + 3 = 38

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

Question 1.
Which congruence criterion do you use in the following?
(a) Given: AC = DF
AB = DE
BC = EF
So, ∆ABC ≅ ∆DEF
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 1
(b) Given: ZX = RP
RQ = ZY
∠PRQ = ∠XZY
So, ∆PQR ≅ ∆XYZ
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 2

(c) Given: ∠MLN = ∠FGH
∠NML = ∠HFG
ML = FG
So, ∆LMN ≅ ∆GFH
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 3

(d) Given EB = BD
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 4
AE = CB
∠A = ∠C = 90°
So, ∆ABE ≅ ∆CDB
Solution:
(a) SSS, as all three sides of AABC are equal to the corresponding sides of ∆DEF.
(b) SAS, as two sides and the angle included between these sides of ∆PQR are equal to the corresponding sides and included angle of ∆XYZ.
(c) ASA, as two angles and the side included between these angles of ∆LMN are equal to the corresponding angles and included side of ∆GFH.
(d) RHS, as in the given two right-angled triangles, one side and the hypotenuse are respectively equal.

Question 2.
You want to show that ∆ART ≅ ∆PEN,
(a) If you have to use SSS criterion, then you need to show
(i) AR =
(ii) RT =
(iii) AT =
(b) If it is given that ∠T = ∠N and you are to use SAS criterion, you need to have
(i) RT = and
(ii) PN =
(c) If it is given that AT = PN and you are to use ASA criterion, you need to have
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 5
Solution:
(a) (i) AR = PE
(ii) RT = EN
(iii) AT = PN

(b) (i) RT = EN
(ii) PN = AT

(c) (i) ∠ATR = ∠PNE
(ii) ∠RAT = ∠EPN

Question 3.
You have to show that ∆AMP ≅ ∆AMQ
In the following proof, supply the missing reasons.
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 6
Solution:
(i) Given
(ii) Given
(iii) Common
(iv) SAS congruence criterion, as the two sides and the angle included between these sides of ∆AMP are equal to corresponding sides and included angle of ∆AMQ.

Question 4.
In ∆ABC, ∠A = 30°, ∠B = 40° and ∠C = 110°
In ∆PQR, ∠P = 30°, ∠Q = 40° and ∠R = 110°
A student says that ∆ABC ≅ ∆PQR by AAA congruence criterion. Is he justified? Why or why not?
Solution:
No. This property represents that these triangles have their respective angles of equal measure. However, this does not give any information about their sides. The sides of these triangles may have a ratio different from 1 : 1. Therefore, AAA property does not prove that two triangles are congruent.

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

Question 5.
In the figure, the two triangles are congruent. The corresponding parts are marked. We can write ∆RAT ≅ ?
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 7
Solution:
It can be observed that,
∠RAT = ∠WON
∠ART = ∠OWN
AR = OW
Therefore, ∆RAT ≅ ∆WON, by ASA criterion.

Question 6.
Complete the congruence statement:
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 8

Solution:
In ∆BCA and ∆BTA,
BC = BT (given)
TA = CA (given)
BA is common.
Therefore, ∆BCA ≅ ∆BTA
(by SSS congruence criterion)
Now, in AQRS and ATPQ,
∠RQS = ∠PTQ (given)
RQ = PT (given)
∠SRQ = ∠QPT (given)
Therefore, ∆QRS = ∆TPQ
(by ASA congruence criterion)

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

Question 7.
In a squared sheet, draw two triangles of equal areas such that
(i) the triangles are congruent.
(ii) the triangles are not congruent. What can you say about their perimeters?
Solution:
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 9
Here, ∆ABC and ∆PQR have the same area and are congruent to each other also. Also the perimeter of both the triangles will be the same.

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 10
Here, ∆ABC and ∆PQR have the same height and same base. Thus, their areas are equal. However, these triangles are not congruent to each other. Also, the perimeter of both the triangles will not be the same.

Question 8.
Draw a rough sketch of two triangles such that they have five pairs of congruent parts but still the triangles are not congruent.
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 11
Solution:
∆ABC & ∆DEF are not congruent to each other but have five congruent parts i.e., ∠BAC = ∠EFD, ∠ABC = ∠DEF, ∠BCA = ∠EDF, AB = DF and BC = EF

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

Question 9.
If ∆ABC and ∆PQR are to be congruent, name one additional pair of corresponding parts. What criterion did you use?
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 12
Solution:
∠ABC = ∠PQR = 90° and
∠BCA = ∠QRP (Given)
For triangles to be congruent, BC = QR
∆ABC ≅ ∆PQR (ASA congruence criterion)

Question 10.
Explain, why ∆ABC ≅ ∆FED
MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2 13
Solution:
Given that, ∠ABC = ∠FED = 90° and ∠BAC = ∠EFD
The two angles of ∆ABC are equal to the two respective angles of ∆FED. Also, the sum of all interior angles of a triangle is 180°. Therefore, third angle of both triangles will also be equal in measure.
∴ ∠BCA = ∠EDF
Now, in ∆ABC and ∆FED,
∠ABC = ∠FED, BC = ED and ∠BCA = ∠EDF
⇒ ∆ABC = ∆FED
(ASA congruence criterion)

MP Board Class 7th Maths Solutions Chapter 7 Congruence of Triangles Ex 7.2

MP Board Class 7th Maths Solutions

MP Board Class 7th Social Science Solutions Miscellaneous Questions 2

MP Board Class 7th Social Science Solutions Miscellaneous Questions 2

Choose the correct answer

Question 1.
The founder of the slave dynasty was:
(a) Mohammed Ghori
(b) Ill-tutmish
(c) Qutub-ud-din Aibak
(d) Alauddin Khilji
Answer:
(c) Qutub-ud-din Aibak

Question 2.
The Chariman of the National Human Rights Commission is appointed by:
(a) Prime Minister
(b) President
(c) Governor
(d) Chief Minister
Answer:
(b) President

Question 3.
The first battle of Panipat was fought in:
(a) 1526 AD
(b) 1556 AD
(c) 1529 AD
(d) 1527 AD
Answer:
(a) 1526 AD

Question 4.
The percentage of land area on earth is:
(a) 71%
(b) 72%
(c) 28%
(d) 29%
Answer:
(d) 29%

MP Board Solutions

Question 5.
Spring tide occurs on:
(a) Fifth day
(b) full moon day
(c) 8th day
(d) 4th day
Answer:
(b) full moon day

Fill in the blanks:

  1. The founder of the Khilji dynasty was ………….
  2. Guru Nanak was bom in ………….. village.
  3. The tenure of the Vice President is …………….. year.
  4. ………….. is used to measure rainfall.
  5. There are …………….number of seasons in India.

Answer:

  1. Alauddin Khilji
  2. Talwandi
  3. Five years
  4. Rain grange
  5. three.

Match column ‘A’with column ‘B’

MP Board Class 7th Social Science Solutions Miscellaneous Questions 2
Answer:
1. (b) Issue of copper coins
2. (c) Riddles-mukris
3. (a) Iqta system
4. (e) Witty, advisor
5. (d) Waves

Answer the following questions in detail:

Question 1.
What are effects of ocean currents on human life?
Answer:
Ocean currents are streams of water flowing constantly in a definite direction at or near the surface of the ocean.
Ocean currents are caused by prevailing or planetary winds. They are also caused by die variation of temperature. The variation of saline water in the sea water causes ocean currents.

The ocean currents influence the climate of the regions such as coastal areas or islands. The warm currents raise the temperature whereas the cold currents reduce the temperature. Due to warm currents the harbors at higher latitudes remain, open through out the jar i. e. The harbors of Norway and Japan. The warm winds blowing over warm currents absorbs a lot of moisture and the nearby areas receive lots of rainfall.

Question 2.
Describe the administrative set up of Shershah.
Answer:
Shershah was an efficient administrator. The interest of the people ranked above everything. He started many reforms in military administration, land revenue etc that was followed by Akbar. Shershah divided his empire into Sarkars, which were again subdivided into parganas.

Officer in charge of sarkars and panganas were periodically transferred. He enforced equal law for justice and introduced a reformed system of currency. The silver coin known as the Rupee which lasted throughout the Mughal period and was maintained by the East India company down to 1835 AD.

MP Board Solutions

Question 3.
Explain the process of the formation of Vidhan Sablia.
Answer:
The representatives of the Vidhan Sabha are elected in such a way that the seats are proportionately represented. If a person is elected from more than one constituency then he will have to resign from the rest retaining only one seat If there is a controversy about the election of any candidate, then a petition can be filed in the High court. After accepting the petition, the High Court gives its verdict It can also be against the candidate.

A person can appeal to the Supreme Court if the Verdict goes against him. The verdict of the Supreme Court is final.
The term of Vidhan Sabha is 5 years. In a case of emergency, it can be dissolved, Vidhan Sabha has a speaker and a Deputy Speaker. The Speaker conducts the business of the state Vidhan Sabha. The Deputy Speaker discharges duties in the absence of the Speaker.

Question 4.
What are the advantages of Ocean?
Answer:

  • Rain on land – All the rain on land are due to the evaporation of sea water. Rains are useful for vegetation, animal life and human beings.
  • Balance of temperature – Ocean shelp to maintain balance of temperature on land.
  • Means of transport – The international trade is possible because of the oceans and seas, which joins the continents.

Question 5.
Write the main features of the architecture of the Sultanate period.
Answer:

  • The caste rules were strictly followed. The women did not enjoy much freedom and the purdah system became very common.
  • The practice of child marriage, polygamy and sati stystem was prevalent in the society.

MP Board Class 7th Social Science Solutions Miscellaneous Questions 2 Short Answer Type Questions

Question 1.
Explain the market control policy of Alauddin Khilji.
Answer:
Alauddin controlled prices in the market Those traders who did not sell goods at fixed prices or who weighed something less, were given severe punishment.

Question 2.
Write the advantages of tides.
Answer:

  • The tides help in fishing.
  • They increase the depth of the shallow harbors. This helps in bringing ships into the harbors.
  • They increase the depth of estuaries.
  • They keep rivers deep enough so to help ships placed in the rivers.

Question 3.
What is meant by ordinance?
Answer:
Ordinance is the order of the Chief Executive issued at a time when the Legislature is not in session. As soon as the legislature is convened, the ordinance is approved by it. If the legislature does not approve them, they are withdrawn.

MP Board Solutions

Question 4.
Write about the progress made in the field of architecture during the reign of Shahjahan.
Answer:
Under Shahjahan Mughal architecture reached die climax. He built magnificent buildings, forts, mosques, tombs in Agra, Lahore, Delhi, Kabul, Kandhar, Ajmer, Ahamdabad etc. He built Moti-Masjid, Diwan-e-Aam, Diwan-e-Khas in the Fort at Agra. The most famous building of his time is the Tajmahal. It is made of white marble. It is regarded as jewel in the builder’s art.

Question 5.
Write a short note on cyclonic rains.
Answer:
When the hot and cold air meet, die hot air rises upwards and the cold air rushes to occupy the low-pressure area in the center. As a result there is circular movement which causes the whirling air in the center to rise upwards. This rising air cools down, condenses and brings rains. This type of rainfall is called cyclonic rain.

Question 6.
Explain the main features of Akbar’s Mansabdari system.
Answer:
‘Mansabdari System’ was a special feature of the Mughal rule. By ‘Mansab’ is meant a post or title. Each ‘Mansabdar’ was recognised as big or small as per the number of soldiers under him. It ranged between 10,000 to 50,000 soliders and the emperor could use their armies as per his wishes.

Question 7.
What was the effect of Bhakti movement on the life of the people?
Answer:
Bhakti movement had a great effect on the Indian society. The leaders of this movement used die local language which put great impact on the minds of die common people. This movement helped in arousing consciousness among people. It removed the false notions and bad practices. It also tried to bring the society together by bridging the gap between Hindu and Muslim.

MP Board Solutions

MP Board Class 7th Social Science Solutions

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.2

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.2

Question 1.
Simplify by combining like terms:
(i) 21b – 32 +7b – 20b
(ii) -z2 + 13z2 – 5z + 7z3 – 15z
(iii) p – (p – q) – q – (q – p)
(iv) 3a – 2b – ab – (a – b + ab) + 3ab + b – a
(v) 5x2y – 5x2 + 3yx2 – 3y2 + x2 – y2 + 8xy2 – 3y2
(vi) (3y2 + 5y – 4) – (8y – y2 – 4)
Solution:
(i) 21b – 32 + 7b – 20b
= 21b + 7b – 20b – 32
= (21 + 7 – 20)b – 32
= 8b – 32

(ii) -z2 + 13z2 – 5z + 7z3 – 15z
= 7z3 + (-1 + 13) z2 + (-5 -15) z
= 7z3 + 12z2 – 20z

(iii) p – (p – q) – q – (q – p)
= p – p + q – q – q + p
= p – q

(iv) 3a – 2b – ab – (a – b + ab) + 3ab + b – a
= 3a – 2b – ab – a + b – ab + 3 ab + b – a
= (3 – 1 – 1)a + (-2 + 1 + 1)b + (-1 – 1 + 3)ab
= a + ab

(v) 5x2y – 5x2 + 3yx2 – 3y2 + x2 – y2 + 8xy2 – 3y2
= (5 + 3) x2y + (-5 + 1) x2 + (- 3 – 1 – 3 )y2 + 8xy2
= 8x2y – 4x2 – 7y2 + 8xy2

(vi) (3y2 + 5y – 4) – (8y – y2 – 4)
= 3y2 + 5y – 4 – 8y + y2 + 4
= (3 + 1) y2 + (5 – 8) y + 4 – 4
= 4y2 – 3y

Question 2.
Add:
(i) 3mn, -5mn, 8mn, -4mn
(ii) t – 8tz, 3tz – z, z – 1
(iii) -7mn + 5, 12mn + 2, 9mn – 8, -2mn – 3
(iv) a + b – 3, b – a + 3, a – b + 3
(v) 14x + 10y – 12xy – 13, 18 – 7x – 10y + 8xy, 4xy
(vi) 5m – 7n, 3n – 4m + 2, 2m – 3mn – 5
(vii) 4x2y, -3xy2, 5xy2, 5x2y
(viii) 3 p2q2 – 4pq + 5, -10p2q2, 15 + 9pq + 7p2q2
(ix) ab – 4a, 4b – ab, 4a – 4b
(x) x2 – y2 – 1, y2 – 1 – x2, 1 – x2 – y2.
Solution:
(i) 3 mn + (-5 mn) + 8 mn + (-4 mn)
= (3 – 5 + 8 – 4 )mn = 2 mn

(ii) (t – 8tz) + (3tz – z) + (z – t)
= t – 8tz + 3tz – z + z – t
= (1 – 1)t + (- 8 + 3)tz + (-1 + 1)z
= -5 tz

(iii) (-7mn + 5) + (12mn + 2) + (9mn – 8) + (-2mn – 3)
=-7mn + 5 + 12mn + 2 + 9mn – 8 – 2mn – 3
= (-7 + 12 + 9 – 2)mn + (5 + 2 – 8 – 3)
= 12mn – 4

(iv) (a + b – 3) + (b – a + 3) + (a – b + 3)
= a + b – 3 + b – a + 3 + a – b + 3
= (1 -1 + 1)a + (1 + 1 – 1)b + (- 3 + 3 + 3)
= a + b + 3

(v) (14x + 10y – 12xy – 13) + (18 – 7x – 10y + 8xy) + 4xy
= 14x + 10y – 12xy – 13 + 18 – 7x – 10y + 8xy + 4xy
= (14 – 7)x + (10 – 10)y + (12 + 8 + 4 )xy + (-13 + 18)
= 7x + 5

(vi) (5m – 7n) + (3n – 4m + 2) + (2m – 3mn – 5)
= 5m – 7n + 3n – 4m + 2 + 2m – 3mn – 5
= (5 – 4 + 2)m + (- 7 + 3)n – 3mn + (2 – 5)
= 3m – 4n – 3mn – 3

(vii) (4x2y) + (-3xy2) + (-5xy2) + (5x2y)
= 4x2y – 3xy2 – 5xy2 + 5x2y
= (4 + 5) x2y + (-3 – 5) xy2
= 9x2y – 8xy2

(viii) (3p2q2 – 4pq + 5) + (-10p2q2) + (15 + 9pq +7p2q2)
= 3p2q2 – 4pq + 5 – 10p2q2 + 15 + 9pq + 7p2q2
= (3 – 10 + 7) p2q2 + (-4 + 9)pq + (5 + 15)
= 5pq + 20

(ix) (ab – 4a) +(4 b – ab) + (4a- 4b)
= ab – 4a + 4b – ab + 4a – 4b
= (1 – 1)ab + (-4 + 4 )a + (4 – 4)b = 0

(x) (x2 – y2 – 1) + (y2 – 1 – x2) + (1 – x2 – y2)
= x2 – y2 – 1 + y2 – 1 – x2 + 1 – x2 – y2
= (1 – 1 – 1)x2 + (-1 + 1 – 1)y2 + (-1 – 1 + 1)
= -x2 – y2 – 1

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.2

Question 3.
Subtract:
(i) -5y2 from y2
(ii) 6xy from -12xy
(iii) (a – b) from (a + b)
(iv) a(b – 5) from b (5 – a)
(v) – m2 + 5 mn from 4mi2 – 3mn + 8
(vi) -x2 + 10x – 5 from 5x – 10
(vii) 5a2 – 7ab + 5b2 from 3ab – 2a2 – 2b2
(viii) 4pq – 5q2 – 3p2 from 5p2 + 3q2 – pq
Solution:
(i) y2 – (-5y2) = y2 + 5y2 = 6y2
(ii) -12xy – (6xy) = -12xy – 6xy = -18xy
(iii) (a + b) – (a – b) = a + b – a + b = 2b

(iv) b(5 – a) – a(b – 5)
= 5b – ab – ab + 5a
= 5a + 5b – 2ab

(v) (4m2 – 3mn + 8) – (- m2 + 5mn)
= 4m2 – 3mn + 8 + m2 – 5mn
= (4 + 1)m2 + (- 3 – 5 )mn + 8
= 5m2 – 8mn + 8

(vi) (5x – 10) – (-x2 + 10x – 5)
= 5x – 10 + x2 – 10x + 5
= x2 + (5 – 10)x + (-10 + 5)
= x2 – 5x – 5

(vii) (3ab – 2a2 – 2b2) – (5a2 – 7ab + 5b2)
= 3ab – 2a2 – 2b2 – 5a2 + 7ab – 5b2
= (3 + 7)ab + (- 2 – 5)a2 + (- 2 – 5 )b2
= 10ab – 7a2 – 7b2

(viii) (5p2 + 3q2 – pq) – (4pq – 5a2 – 3p2)
= 5p2 + 3q2 – pq – 4pq + 5q2 + 3p2
= (5 + 3 )p2 + (3 + 5 )q2 + (-1 – 4 )pq
= 8p2 + 8q2 – 5pq

Question 4.
(a) What should be added to x2 + xy + y2 to obtain 2x2 + 3xy?
(b) What should be subtracted from 2a + 8b + 10 to get – 3a + 7b + 16?
Solution:
(a) Let a be the required term.
∴ a + (x2 + y2 + xy) = 2x2 + 3xy
⇒ a = 2x2 + 3xy – (x2 + y2 + xy)
= 2x2 + 3xy – x2 – y2 – xy
= (2 – 1) x2 – y2 + (3 – 1)xy
= x2 – y2 + 2xy

(b) Let p be the required term.
∴ (2a + 8b + 10) -p = -3a + 7b + 16
⇒ p = 2a + 8b + 10 – (- 3a + 7b + 16)
= 2a + 8b + 10 + 3a – 7b – 16
= (2 + 3)a + (8 – 7)b + (10 – 16)
= 5a + b – 6

Question 5.
What should be taken away from 3x2 – 4y2 + 5xy + 20 to obtain -x2 – y2 + 6xy + 20 ?
Solution:
Required term
= (3x2 – 4y2 + 5xy + 20) – (-x2 – y2 + 6xy + 20)
= 3x2 – 4y2 + 5xy + 20 + x2 + y2 – 6xy – 20
= (3 + 1)x2 + (- 4 + 1) y2 + (5 – 6)xy + (20 – 20)
= 4x2 – 3y2 – xy

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.2

Question 6.
(a) From the sum of 3x – y + 11 and -y – 11, subtract 3x – y – 11.
(b) From the sum of 4 + 3x and 5 – 4x + 2x2, subtract the sum of 3x2 – 5x and -x2 + 2x + 5.
Solution:
(a) Sum of 3x – y + 11 and – y – 11
= (3x – y + 11) + (-y – 11)
= 3x – y + 11 – y – 11
= 3x + (- 1 – 1) y + (11 – 11)
= 3x – 2y
Now, required difference
= (3x – 2y) – (3x – y – 11)
= 3x – 2y – 3x + y + 11
= (3 – 3)x + (- 2 + 1) y + 11
= -y + 11

(b) Sum of 4 + 3x and 5 – 4x + 2x2
= (4 + 3x) + (5 – 4x + 2x2)
= 4 + 3x + 5 – 4x + 2x2
= (3 – 4)x + 2x2 + 4 + 5
= – x + 2x2 + 9
Now, sum of 3x2 – 5x and -x2 + 2x + 5
= (3x2 – 5x) + (-x2 + 2x + 5)
= 3x2 – 5x – x2 + 2x + 5
= (3 – 1) x2 + (- 5 + 2)x + 5
= 2x2 – 3x + 5
Required difference
= (- x + 2x2 + 9) – (2x2 – 3x + 5)
= -x + 2x2 + 9 – 2x2 + 3x – 5
= (-1 + 3)x + (2 – 2) x2 + (9 – 5)
= 2x + 4

MP Board Class 7th Maths Solutions

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1

Question 1.
Get the algebraic expressions in the following cases using variables, constants and arithmetic operations.
(i) Subtraction of z from y.
(ii) One-half of the sum of numbers x and y.
(iii) The number z multiplied by itself.
(iv) One-fourth of the product of numbers p and Q.
(v) Numbers x and y both squared and added.
(vi) Number 5 added to three times the product of numbers m and n.
(vii) Product of numbers y and z subtracted from 10.
(viii) Sum of numbers a and b subtracted from their product.
Solution:
(i) y – z
(ii) \(\frac{1}{2}\)(x + y)
(iii) z2
(iv) \(\frac{1}{4}\)(pq)
(v) x2 + y2
(vi) 5 + 3 (mn)
(viii) ab – (a + b)

Question 2.
(i) Identify the terms and their factors in the following expressions. Show the terms and factors by tree diagrams.
(a) x – 3
(b) 1 + x + x2
(c) y – y3
(d) 5xy2 + 7x2y
(e) -ab + 2b2 – 3a2

(ii) Identify terms and factors in the expressions given below:
(a) -4x + 5
(b) -4x + 5y
(c) 5y + 3y2
(d) xy + 2x2y2
(e) pq + q
(f) 1.2ab – 2.4b + 3.6a
(g) \(\frac{3}{4}\)x + \(\frac{1}{4}\)
(h) 0.1p2 + 0.2q2
Solution:
(i)
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1 1
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1 2

Question 3.
Identify the numerical coefficients of terms (other than constants) in the following expressions:
(i) 5 – 3t2
(ii) 1 + t + t2 + t3
(iii) x + 2xy + 3y
(iv) 100m + 1000n
(v) -p2q2 + 7pq
(vi) 1.2a + 0.8b
(vii) 3.14 r2
(viii) 2(l + b)
(ix) 0.1y + 0.01y2
Solution:
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1 3
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1 4

MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1

Question 4.
(a) Identify terms which contains x and give the coefficient of x.
(i) y2x + y
(ii) 13y2 – 8yx
(iii) x + y + 2
(iv) 5 + z + zx
(v) 1 + x + xy
(vi) 12xy2 + 25
(vii) 7x + xy2
(b) identify terms which contains y2 and give the coefficient of y2.
(i) 8 – xy2
(ii) 5y2 + 7x
(iii) 2x2y – 15xy2 + 7y2
Solution:
(a)
MP Board Class 7th Maths Solutions Chapter 12 Algebraic Expressions Ex 12.1 5

Question 5.
Classify into trinomials.
(i) 4y – 7z
(ii) y2
(iii) x + y – xy
(iv) 100
(v) ab – a – b
(vi) 5 – 3t
(vii) 4p2q – 4pq2
(viii) 7mn
(ix) z2 – 3z + 8
(x) a2 + b2
(xi) z2 + z
(xii) 1 + x + x2
Solution:
The monomials, binomials and trinomials have 1, 2 and 3 unlike terms in it respectively.
(i) 4y – 7z Binomial
(ii) y2 Monomial
(iii) x + y – xy Trinomial
(iv) 100 Monomial
(v) ab – a – b Trinomial
(vi) 5 – 3t Binomial
(vii) 4p2q – 4pq2 Binomial
(viii) 7mn Monomial
(ix) z2 – 3z + 8 Trinomial
(x) a2 + b2 Binomial
(xi) z2 + z Binomial
(xii) 1 + x + x2 Trinomial

MP Board Solutions

Question 6.
State whether a given pair of terms is of like or unlike terms.
(i) 1,100
(ii) -7x, \(\frac{5}{2}\)x
(iii) -29x, -29y
(iv) 14xy, 42yx
(v) 4m2p, 4mp2
(vi) 12xz, 12x2z2
Solution:
The terms which have same algebraic factors are called like terms. However, when terms have different algebraic factors, these are called unlike terms.
(i) 1,100 Like
(ii) -7x, \(\frac{5}{2}\)x Like
(iii) -29x, -29y Unlike
(iv) 14xy, 42yx Like
(v) 4m2p, 4mp2 Unlike
(vi) 12xz, 12x2z2 Unlike

Question 7.
Identify like terms in the following:
(a) -xy2, -4yx2, 8x2, 2xy2, 7y, -11x2, -100x, -11yx, 20x2y, -6x2, y, 2xy, 3x
(b) 10pg, 7p, 8q, -p2q2, -7qp, – 100q, -23, 12q2p2, – 5p2, 41, 2405p, 78qp, 13p2g, qp2,701p2
Solution:
(a) -xy2 and 2xy2; -4yx2 and 20x2y; 8x2, -11x2 and -6x2; 7y and y, -100x and 3x; -11yx and 2xy

(b) 10pq, -7qp and 78qp; 7p and 2405p; 8q and -100y; -p2q2 and 12q2p2, -23 and 41; -5p2 and 701 p2; 13p22q and qp2

MP Board Class 7th Maths Solutions