How to factor $(x^5+1) (x^5-1) $ I have this:
$ (x^5+1) (x^5-1) $
And I don't know how to continue factor.
Geogebra's Factor says:
$(x+1)(x-1)(x^4-x^3+x^2-x+1)(x^4+x^3+x^2+x+1)$

Since $-1$ is a root of $x^5+1$, we know that it is divisible by $x+1$.  Likewise, since $1$ is a root of $x^5-1$, we know that it is divisible by $x-1$.  You can use polynomial long division to obtain the other factors.
