Question

This is the exercise 4.3 of chapter 4 of class 7 ncert so please solve this.....​

Answer 1

Answer:

a) 2(x + 4) = 12

⇒ \frac{2(x+4)}{2}=\frac{12}{2} (Dividing both sides by 2)

⇒ x + 4 = 6

⇒ x = 6 – 4 (Transposing 4 to RHS)

⇒ x – 2

Check: Put x = 2 in LHS

2(2 + 4) = 2 × 6 = 12 RHS as required

 

(b) 3(n – 5) = 21

⇒ \frac{3(n-5)}{3}=\frac{21}{3} (Dividing both sides by 3)

⇒ n – 5 = 7

⇒ n = 7 + 5 (Transposing 5 to RHS)

n = 12

Check: Put n = 12 in LHS

3(12 – 5) = 3 × 7 = 21 RHS as required

(c) 3(n – 5) = -21

⇒ \frac{3(n-5)}{3}=\frac{-21}{3} (Dividing both sides by 3)

⇒ n – 5 = -7

⇒ n = -7 + 5 (Transposing 5 to RHS)

⇒ n = -2

Check: Put n = -2 in LHS

3(-2 – 5) = 3 × -7

= -21 RHS as required

 

(d) -4(2 + x) = 8

⇒ \frac{-4(2+x)}{-4}=\frac{8}{-4} (Dividing both sides by -4)

⇒ 2 + x = -2

⇒ x = -2 – 2 (Transposing 2 to RHS)

⇒ x = —4

Check: Put x = -4 in LHS

-4(2 – 4) = -4 × -2 = 8 RHS as required

(e) 4(2-x) = 8

⇒ \frac{4(2-x)}{4}=\frac{8}{4} (Dividing both sides by 4)

⇒ 2 – x = 2 – 2 (Transposing 2 to RHS)

⇒ -x = 0

∴ x = 0 (Multiplying both sides by -1)

Check: Put x = 0 in LHS

4(2 – 0) = 4 × 2 = 8 RHS as required

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Answer 2

Answer:

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