Let P(x)=x4−1P(x) = x^4 - 1P(x)=x4−1. By factoring, express P(x)P(x)P(x) as a product over real numbers.
(x−1)(x+1)(x2+1)(x - 1)(x + 1)(x^2 + 1)(x−1)(x+1)(x2+1)
(x2−1)2(x^2 - 1)^2(x2−1)2
(x−1)2(x+1)2(x - 1)^2(x + 1)^2(x−1)2(x+1)2
(x2−1)(x+1)(x−1)(x^2 - 1)(x + 1)(x - 1)(x2−1)(x+1)(x−1)