You may want to review simplifying roots with variables first.

If the radicand has a denominator, we deal with it just as we did without variables. For example, if you have to simplify √(2 ⁄ a2), this is the same as √(1 ⁄ a2)√2 = 1 ⁄ a * √2. In general, when you're done, there should be no denominator in the radicand.

As before, it works the same way for higher-order roots.