$${\sqrt[{{\mathtt{{\mathtt{3}}}}}]{{\mathtt{x}}}} = {\sqrt{{\frac{{\mathtt{x}}}{{\sqrt[{{\mathtt{{\mathtt{3}}}}}]{{\mathtt{x}}}}}}}}$$
it solves out fine manually and all its just interesting.
yeah, positive x cause of imaginary numbers. also it works for any $${\sqrt[{{\mathtt{{\mathtt{n}}}}}]{{\mathtt{x}}}} = {\sqrt[{{\mathtt{\left({\mathtt{n}}{\mathtt{\,-\,}}{\mathtt{1}}\right)}}}]{{\frac{{\mathtt{x}}}{{\sqrt[{{\mathtt{{\mathtt{n}}}}}]{{\mathtt{x}}}}}}}}$$