х^3-х^2y-xy^2+y^3 = (x^3-x^2y)-(xy^2-y^3) = x^2(x-y)-y^2(x-y) = (x-y)(x^2-y^2) = (x-y)(x-y)(x+y) = (x-y)^2*(x+y)
х^3-х^2y-xy^2+y^3 = (x^3-x^2y)-(xy^2-y^3) = x^2(x-y)-y^2(x-y) = (x-y)(x^2-y^2) = (x-y)(x-y)(x+y) = (x-y)^2*(x+y)