Question 276444
x^2-y^2-ax-ay

(x+y)(x-y) - a(x+y)

(x+y){ x-y -ax+ay)
(x+y){ x-ax-y+ay}
(x+y){x(1-a)-y(1-a)}
(x+y){(1-a)(x-y)}
(x+y)(x-y)(1+a)