Ads Blocker Image Powered by Code Help Pro

Ads Blocker Detected!!!

We have detected that you are using extensions to block ads. Please support us by disabling these ads blocker.

Mathematics Class 7 – Chapter 4 – Simple Equation – Exercise – 4.2 – NCERT Exercise Solution

1. Give first the step you will use to separate the variable and then solve the equation:

(a) x – 1 = 0

Solution:

Adding 1 to both the side of given equation,

 we get,

 x – 1 + 1 = 0 + 1

x = 1

(b) x + 1 = 0

Solution:

Subtracting 1 to both the side of given equation,

we get,

x + 1 – 1 = 0 – 1

 x = – 1

(c) x – 1 = 5

Solution:

Adding 1 to both the side of given equation,

we get,

 x – 1 + 1 = 5 + 1

 x = 6

(d) x + 6 = 2

Solution:

Substracting 6 to both the side of given equation,

 we get,

x + 6 – 6 = 2 – 6

x = – 4

(e) y – 4 = – 7

Solution:

Adding 4 to both the side of given equation,

we get,

y – 4 + 4 = – 7 + 4

 y = – 3

(f) y – 4 = 4

Solution:

Adding 4 to both the side of given equation,

we get,

 y – 4 + 4 = 4 + 4

 y = 8

(g) y + 4 = 4

Solution:

Substracting 4 to both the side of given equation,

 we get,

= y + 4 – 4 = 4 – 4

= y = 0

(h) y + 4 = – 4

Solution:

Substracting 4 to both the side of given equation,

 we get,

= y + 4 – 4 = – 4 – 4

= y = – 8

2. Give first the step you will use to separate the variable and then solve the equation:

(a) 3l = 42

Solution:

Dividing both sides of the equation by 3,

we get,

3l/3 = 42/3

l = 14

(b) b/2 = 6

Solution:

Multiplying both sides of the equation by 2,

we get,

b/2 × 2= 6 × 2

b = 12

(c) p/7 = 4

Solution:

Multiplying both sides of the equation by 7,

we get,

p/7 × 7= 4 × 7

p = 28

(d) 4x = 25

Solution:

Dividing both sides of the equation by 4,

we get,

4x/4 = 25/4

x = 25/4

(e) 8y = 36

Solution:

Dividing both sides of the equation by 8,

we get,

8y/8 = 36/8

x = 9/2

(f) (z/3) = (5/4)

Solution:

Multiplying both sides of the equation by 3,

we get,

(z/3) × 3 = (5/4) × 3

x = 15/4

(g) (a/5) = (7/15)

Solution:

Multiplying both sides of the equation by 5,

we get,

(a/5) × 5 = (7/15) × 5

a = 7/3

(h) 20t = – 10

Solution:

Dividing both sides of the equation by 20,

we get,

20t/20 = -10/20

x = – ½

3. Give the steps you will use to separate the variable and then solve the equation:

(a) 3n – 2 = 46

Solution:

In step 1 we add 2 to the both sides of the equation,

we get,

3n – 2 + 2 = 46 + 2

= 3n = 48

In step 2 we divide both sides of the equation by 3,

we get,

3n/3 = 48/3

n = 16

(b) 5m + 7 = 17

Solution:

In step 1 we subtract 7 to the both sides of the equation,

we get,

 5m + 7 – 7 = 17 – 7

 5m = 10

In step 2 we divide both sides of the equation by 5,

we get,

5m/5 = 10/5

m = 2

(c) 20p/3 = 40

Solution:

In step 1 we multiply both sides of the equation by 3,

we get,

 (20p/3) × 3 = 40 × 3

 20p = 120

In step 2 we divide both sides of the equation by 20,

 we get,

 20p/20 = 120/20

 p = 6

(d) 3p/10 = 6

Solution:

In step 1 we multiply both sides of the equation by 10,

we get,

(3p/10) × 10 = 6 × 10

3p = 60

In step 2 we divide both sides of the equation by 3,

Then, we get,

 3p/3 = 60/3

 p = 20

4. Solve the following equations:

(a) 10p = 100

Solution:

Dividing both sides of the equation by 10,

we get,

10p/10 = 100/10

p = 10

(b) 10p + 10 = 100

Solution:

Subtracting 10 to the both sides of the equation,

we get,

10p + 10 – 10 = 100 – 10

10p = 90

Now,

Dividing both sides of the equation by 10,

we get,

 10p/10 = 90/10

p = 9

(c) p/4 = 5

Solution:

Multiplying both sides of the equation by 4,

we get,

p/4 × 4 = 5 × 4

p = 20

(d) – p/3 = 5

Solution:

Multiplying both sides of the equation by – 3,

we get,

– p/3 × (- 3) = 5 × (- 3)

p = – 15

(e) 3p/4 = 6

Solution:

Multiplying both sides of the equation by 4,

we get,

 (3p/4) × (4) = 6 × 4

 3p = 24

Now,

Dividing both sides of the equation by 3,

we get,

 3p/3 = 24/3

 p = 8

(f) 3s = – 9

Solution:

Dividing both sides of the equation by 3,

we get,

3s/3 = -9/3

s = -3

(g) 3s + 12 = 0

Solution:

Substracting 12 to the both sides of the equation,

we get,

3s + 12 – 12 = 0 – 12

3s = -12

Now,

Dividing both sides of the equation by 3,

we get,

 3s/3 = -12/3

 s = – 4

(h) 3s = 0

Solution:

Dividing both sides of the equation by 3,

 we get,

3s/3 = 0/3

s = 0

(i) 2q = 6

Solution:

Dividing both sides of the equation by 2,

we get,

2q/2 = 6/2

q = 3

(j) 2q – 6 = 0

Solution:

Adding 6 to the both sides of the equation,

we get,

2q – 6 + 6 = 0 + 6

2q = 6

Now,

Dividing both sides of the equation by 2,

we get,

2q/2 = 6/2

q = 3

(k) 2q + 6 = 0

Solution:

Subtracting 6 to the both sides of the equation,

we get,

2q + 6 – 6 = 0 – 6

2q = – 6

Now,

Dividing both sides of the equation by 2,

we get,

2q/2 = – 6/2

q = – 3

(l) 2q + 6 = 12

Solution:

Subtracting 6 to the both sides of the equation,

we get,

2q + 6 – 6 = 12 – 6

2q = 6

Now,

Dividing both sides of the equation by 2,

we get,

2q/2 = 6/2

q = 3

👍👍👍

Leave a Comment

error: