Question

a^2-b^2-a+b
a^2-b^2-a+b
x^3-x^2y-xy^2+y^3

Answer 1

a^2-b^2-a+b=(a-b)(a+b)-(a+b)=(a+b)(a-b-1)
x^3-x^2y-xy^2+y^3=x^2(x-y)-y^2(-x+y)=(x-y)(x^2-y^2)