If $x - 1/x = u$ , what's $x^3 - 1/x^3$ ?

Ref: R9928

If $x - \dfrac{1}{x} = u$ , express $x^3 - \dfrac{1}{x^3}$ and $x^5 - \dfrac{1}{x^5}$ in terms of $u$ .

What happens if we square $u$ ?

If x−1/x=ux - 1/x = u, what's x3−1/x3x^3 - 1/x^3?