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A day full of math games & activities. Find one near you.

Give first the step you will use to separate the variable and then solve the equation:
(a) 3l = 42   (b) b/2 = 6   (c) p/7 = 4
(d) 4x = 25   (e) 8y = 36   (f) z/3 = 5/4
(g) a/5 = 7/15   (h) 20t = −10

Solution:

We use the basic concepts of simple linear equations in one variable to solve the questions given.

Try to reduce the equation by multiplying or dividing both sides of the equation by the same number to obtain the value of the variable.

(a) 3l = 42

Divide both the sides by 3 we get,

3l/3 = 42/3

l = 14

(b) b/2 = 6

Multiplying both sides by 2 we get,

(b/2) × 2 = 6 × 2

b = 12

(c) p/7 = 4

Multiplying both sides by 7 we get,

(p/7) × 7 = 4 × 7

p = 28

(d) 4x = 25

Dividing both the sides by 4 we get,

4x/4 = 25/4

x = 25/4

(e) 8y = 36

Dividing both the sides by 8 we get,

8y/8 = 36/8

y = 9/2

(f) z/3 = 5/4

Multiplying both sides by 3 we get,

(z/3) × 3 = (5/4) × 3

z = 15/4

(g) a/5 = 7/15

Multiplying both sides by 5 we get,

(a/5) × 5 = (7/15) × 5

a = 7/3

(h) 20t = -10

Dividing both sides by 20 we get,

20t/20 = -10/20

t = -1/2

☛ Check: NCERT Solutions for Class 7 Maths Chapter 4

Video Solution:

Give first the step you will use to separate the variable and then solve the equation: (a) 3l = 42 (b) b/2 = 6 (c) p/7 = 4 (d) 4x = 25 (e) 8y = 36 (f) z/3 = 5/4 (g) a/5 = 7/15 (h) 20t = −10

NCERT Solutions for Class 7 Maths Chapter 4 Exercise 4.2 Question 2

Summary:

We have given the first step that will be used to separate the variable and then solve the equation: (a) 3l = 42;  l = 14 (b) b/2 = 6; b = 12 (c) p/7 = 4; p = 28 (d) 4x = 25; x = 25/4 (e) 8y = 36; y = 9/2 (f) z/3 = 5/4; z = 15/4 (g) a/5 = 7/15; a = 7/3 (h) 20t = −10; t = -1/2

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