Question

Factorise fully :

4(x - y)^2 - 9(x + y)^2​

Answer 1

Explanation:

4(x^2-2xy+y^2)-9(x^2+2xy+y^2)

4x^2-8xy+4y^2-9x^2-18xy-9y^2

-5x^2-26xy-5y^2

-5x^2-xy-25xy-5y^2

-x(5x+y)-5y(5x+y)

(-x-5y)(5x+y) or you can also remove the negative one to get

-(x+5y)(5x+y)

Answer 2

- ( 5x + y ) ( x + 5y )

or

-5x^2 - 5y^2 - 26xy