Factorize \(9(x + y)^2- 4(x - y)^2\)

  • A (x + y)(5x + y)
  • B (x + y)^2
  • C (x + 5y)(5x + y)
  • D 5(x + y)^2
jamb 1990mathematics

The correct answer is C. (x + 5y)(5x + y)

9(x + y)

- 4(x - y)

Using difference of two squares which says

a

- b

= (a + b)(a - b) = 9(x + y)

- 4(x - y)

= [3(x + y)]

- [2(x - y)]

= [3(x + y) + 2(x - y) + 2(x - y)][3(x + y) - 2(x - y)]

= [3x +3y + 2x - 2y][3x + 3y - 2x + 2y]

= (5x + y)(x + 5y)

Previous question Next question