Thread: Number theory factor problem

Verify that if n is composite, i.e. n = ab, then the polynomial x^n - 1factors as:

x^n - 1 = (x^b - 1) ( x^b(a - 1) + x^b(a - 2) + ... + x^b + 1)

Any hints? What's the major theorem we're using? Fermat's little theorem?

Ok, never mind, I got the problem. If you just take the right side and multiply it then just add all the terms, we'll end up with the left side.