No radicand (expression within the radical) has factors which are powers of the type of radical. For square roots this means that there are no perfect square factors in any radicands.
There are no radicals in a denominator
There are no fractions within a radicand.
Your expression has a radical in the denominator. The denominator is just a single term and this is the easiest kind of denominator to "fix". What we need to do is figure out a number, by which we will multiply the numerator and denominator, which will turn the denominator into a perfect square.
In this case we will multiply the nuerator and denominator by :
This simplifies to:
or
This expression passes all three tests for a simplified radical expression.
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