в) $$x^3 - x^2y - x + y = (x^3 - x^2y) + (-x + y) = x^2(x - y) - (x - y) = (x - y)(x^2 - 1) = (x - y)(x - 1)(x + 1)$$
Ответ: $$(x - y)(x - 1)(x + 1)$$