i. x – 4 = 3 ….(i)
Substituting x = – 1 in L.H.S. of equation (i),
L.H.S. = (-1) – 4 = – 5
R.H.S. = 3
∴ L.H.S. ≠ R.H.S
∴ x = – 1 is not the solution of the given equation.
Substituting x = 7 in L.H.S. of equation (i),
L.H.S. = (7) – 4 = 3
R.H.S. = 3
∴ L.H.S. = R.H.S.
∴ x = 7 is the solution of the given equation.
Substituting x = – 7 in L.H.S. of equation (i),
L.H.S. = (- 7) – 4 = -11
R.H.S. = 3
∴ L.H.S. ≠ R.H.S.
∴ x = – 7 is not the solution of the given equation.
ii. 9m = 81 …(i)
Substituting m = 3 in L.H.S. of equation (i),
L.H.S. = 9 × (3) = 27
R.H.S. = 81
∴ L.H.S. ≠ R.H.S.
∴ m = 3 is not the solution of the given equation.
Substituting m = 9 in L.H.S. of equation (i),
L.H.S. = 9 × (9) = 81
R.H.S. = 81
∴ L.H.S. = R.H.S.
∴ m = 9 is the solution of the given equation.
Substituting m = – 3 in L.H.S. of equation (i),
L.H.S. = 9 × (- 3) = -27
R.H.S. = 81
∴ L.H.S. ≠ R.H.S.
∴ m = – 3 is not the solution of the given equation.
iii. 2a + 4 = 0 …..(i)
Substituting a = 2 in L.H.S. of equation (i),
L.H.S. = 2 (2) + 4 = 4 + 4 = 8
R.H.S. = 0
∴ L.H.S. ≠ R.H.S.
∴ a = 2 is not the solution of the given equation.
Substituting a = – 2 in L.H.S. of equation (i),
L.H.S. = 2(-2)+ 4
= -4 + 4
= 0
R.H.S. = 0
∴ L.H.S. = R.H.S.
∴ a = – 2 is the solution of the given equation.
Substituting a = 1 in L.H.S. of equation (i),
L.H.S. = 2(1)+ 4 = 2 + 4 = 6
R.H.S. = 0
∴ L.H.S. ≠ R.H.S.
∴ a = 1 is not the solution of the given equation.
iv. 3 – y = 4 …(i)
Substituting y = -1 in L.H.S. of equation (i),
L.H.S. = 3 – (- 1)
= 3 + 1
= 4
R.H.S. = 4
∴ L.H.S. = R.H.S.
∴ y = – 1 is the solution of the given equation.
Substituting y = 1 in L.H.S. of equation (i),
L.H.S. = 3 -(1) = 2
R.H.S. = 4
∴ L.H.S. ≠ R.H.S.
∴ y = 1 is not the solution of the given equation.
Substituting y = 2 in L.H.S. of equation (i),
L.H.S. = 3-(2) = 1
R.H.S. = 4
∴ L.H.S. ≠ R.H.S.
∴ y = 2 is not the solution of the given equation.
