factorize

Question

x^4 - (x-z)^4

Answer 1

(x^2 + (x-z)^2)(x^2 - (x-z)^2)
= (x^2 + (x-z)^2)(x + x-z)(x - x+z)
= z(2x-z)(x^2 + (x-z)^2)