b) x^3 – y^3 + x^2y – xy^2;
b) x3 – y3 + x2y – xy2;
b) x3 – y3 + x2y – xy2 = (x3 + x2y) – (y3 + xy2)
= (x3 + x2y) – (y3 + xy2) = x2(x + y) – y2(x + y)
= (x + y)(x2 – y2) = (x + y)(x + y)(x – y) = (x + y)2(x – y);