Question

Factorise x²-15xy-54y²​

Answer 1

Step-by-step explanation:

x^2-18xy+3xy-54y^2

x(x-18y)+3y(x-18y)

(x+3y)(x-18y)

Answer 2

Step-by-step explanation:

${x}^{2} - 15xy - 54 {y}^{2} \\ = {x}^{2} - (18 - 3)xy - 54 {y}^{2} \\ = {x}^{2} - 18xy + 3xy - 54 {y}^{2} \\ = x \: (x - 18y) \: + 3y \: (x - 18y) \\ = (x - 18y) \: (x + 3y)$