You may want to review simplifying roots without variables and taking them with variables first.

If the radicand has variables in it, we can deal with them too.
For example, √(2*a*^{3}) =
√(*a*^{2})√(2*a*)
= *a*√(2*a*). You're done when
the *coefficient* on the radicand isn't divisible by any
squares (just as before) and none of the variables in the radicand
have exponents.

As before, we can do the same thing with higher roots. For cube roots, for example, you're done when the coefficient on the radicand isn't divisible by any cubes and none of the variables in the radicand have exponents higher than 2.