Expressx^4 - xin its fully factorise form.

I went through factorising methods:

common factor

difference of two squaresX

breaking bracketsX

quadratic formulaX

polynomial?

I would say answer =x(x^3 - 1)

But that is way to simple for the level i'm taking, so im asking if polynomials are involved here? If not, what else should i try?

Please don't show me the solution, just answer yes/no.

Thanks