x4 - 1 = (x2 + 1)(x + 1)(x - 1).
(x - 1)(x + 1)
(x + 1)(x - 8)
x(x-1)
(x - 1)(x - 1)(x - 1) - (x + 1)(x + 1)(x + 1)
(x + 3)(x - 1)(x + 1)
x(x + 1)(x - 1)
(x - 3)(x + 3)(x2 + 9)
x(x + 1)(x -1)
x(x - 1)
(x - 1)(x^2 + x + 1)
(x - 1)(x^2 + x + 1)
x^2(1 - x)(1 + x)