Question

Factorise: 25(x+y)²-9(x-y)²

Answer 1

5²(x+y)²-3²(x-y)²
(5(x+y))²-(3(x-y))²
(5x+5y)²-(3x-3y)²
(5x+5y+3x-3y)(5x+5y-(3x-3y))
(8x+2y)(5x+5y-3x+3y)
(8x+2y)(2x+8y)
2(4x+y)(x+4y)
this is answer