Question

Factorise the following:

x² – 9y²

Answer 1

Given expression: x² – 9y²

Step-wise calculation:

1. Recognize this as a difference of squares because 9y² = (3y)².

2. Use the identity a² – b² = (a + b)(a – b), where a = x and b = 3y.

x² – 9y² = x² – (3y)²

x² – 9y² = (x + 3y)(x – 3y)

The factorised form of (x² – 9y²) is (x + 3y)(x – 3y).