Question

Verify the following:
(a) 18 × [ 7 + (–3)] = [18 × 7] + [18 × (–3)]
(b) (–21) × [(– 4) + (– 6)] = [(–21) × (– 4)] + [(–21) × (– 6)]

Answer 1

(a) 18 × [7 + (-3)] = [18 × 7] + [18 × (-3)]
LHS = 18 × [7 + (-3)] = 18 × 4 = 72
RHS = [18 × 7] + [18 × (-3)] = 126 + (-54)
= 126 – 54 = 72
LHS = RHS
Hence, verified.
(b) (-21) × [(-4) + (-6)] = [(-21) × (-4)] + [(-21) × (-6)]
LHS = (-21) × [(-4) + (-6)]
= (-21) × (-10)
= (-) × (-) × 21 × 10 = 210
RHS = [(-21) × (-4)] + [(-21) × (-6)]
= (84) + (126) = 84 + 126 = 210
LHS = RHS
Hence, verified.