Question

Use the formula to expand:

(4) (3b – 6 + m)²

Answer 1

We know that (x + y + z)² = x² + y² + z² + 2xy + 2yz + 2xz
Comparing (3b – 6 + m)² with (x + y + z)² , we get:
x = 3b, y = –6 and z = m
Substituting these in the above formula:
(3b – 6 + m)² = (3b)² + (–6)² + (m)² + 2 × 3b × (–6) + 2 × (–6) × (m) + 2 × 2 × (m) × 3b
= 9b² + 36 + m² – 36b – 12m + 6mb