# CBSE NCERT Solutions for Class 7 Chapter 4

The solutions for class 7 provide students a fine preparation strategy in order to prepare for their exam more methodically. Students get a fair idea on the subject, the sort of questions that are possibly asked and the method to answer them.

**CBSE NCERT Solutions for Class 7 Maths Chapter 4:**

*Question-1*:

Check whether the value given in the brackets is a solution to the given equation or not:

(a) n+5=19(n=1)

(b) 7n+5=19(n=-2)

(c) 7n+5=19(n=2)

(d) 4p-3=13(p=1)

(e) 4p-3=13(p=-4)

*Solution*:

(a) n+5=19(n=1)

Putting n=1 in L.H.S.,

1+5=6

∵ L.H.S ≠ R.H.S

∴ n=1 is not the solution of given equation.

(b) 7n+5=19 (n=2)

Putting n=-2 in L.H.S.

7(-2)+5=-14+5=-9

∵ L.H.S ≠ R.H.S

∴ n=-2 is not the solution of given equation.

(c) 7n+5 = 19 (n=2)

Putting n=2 in L.H.S

7(2)+5=14+5=19

∵ L.H.S =R.H.S,

∴ n=2 is the solution of given equation.

(d) 4p-3=13(p=1)

4(1) – 3=4 – 3=1

∵ L.H.S ≠ R.H.S.,

∴ p=1 is not the solution of given equation.

(e) 4p-3=13(p=4)

Putting p = -4 in L.H.S,

4(-4)-3=-16-3=-19

∵ L.H.S ≠ R.H.S.,

∴ p=0 is not the solution of given equation.

*Question-2*:

Solve the following equations by trial and error method:

(i) 5 p+ 2 = 17

(ii) 3m- 14 = 4

*Solution*:

(i) Putting p = -3 in L.H.S 5 (-3 ) + 2 = -15 + 2 = -13

∵ -13 ≠ 17 Therefore, , p = -3 is not the solution.

Putting p=-2 in L.H.S 5 (-2) + 2 = -10 + 2 = -8

∵ -8 ≠ 17 Therefore , p=-2 is not the solution.

Putting p=-1 in L.H.S 5(-1)+2=-5+2=-3

∵ -3 ≠ 17 Therefore, p = -1 is not the solution.

Putting p=0 in L.H.S 5(0)+2=0+2=2

∵ 2 ≠ 17 therefore p=0 is not the solution.

Putting p=1 in L.H.S 5(1)+2=5+2=7

∵ 7 ≠ 17 Therefore, p = 1 is not the solution.

Putting p=2 in L.H.S 5(2)+2=5+2=7

∵ 12 ≠ 17 Therefore, p=1 is not the solution.

Putting p=2 in L.H.S 5(2) +2=10+2=12

∵ 12 ≠ 17 Therefore, p=2 is not the solution.

Putting p=3 in L.H.S 5(3)+2=15=17

∵ 17=17 Therefore, p=3 is the solution.

(ii) 3m-14=4

Putting m=-2 in L.H.S 3(-2)-14=-6-14=-20

∵ -20 ≠ 4 Therefore, m=-2 is not the solution.

Putting m=-1 in L.H.S 3(-2) -14=-6-14=-20

∵-20 ≠ 4 Therefore, m=-2 is not the solution.

Putting m=-1 in L.H.S 3(-1) -14=-3-14=-17

∵-17 ≠ 4 Therefore, m = -1 is not the solution.

Putting m=0 in L.H.S 3(0)-14=0-14=-14

∵-14 ≠ 4 Therefore, m=0 is not the solution.

Putting m=1 in L.H.S 3(1)-14=3-14=-11

∵-11 ≠ 4 Therefore, m=1 is not the solution.

Putting m=2 in L.H.S 3(2) -14=6-14=-8

∵-8 ≠ 4 Therefore, m=2 is not the solution.

Putting m=3 in L.H.S 3(3)-14=9-14=-5

∵-2 ≠ 4 Therefore, m=4 is not the solution.

Putting m=5 in L.H.S 3(5)-14=15-14=1

∵1 ≠ 4 Therefore, m=5 is not the solution.

Putting m=6 in L.H.S 3(6)-14=18-14=4

∵ 4=4 Therefore, m=6 is not the solution.