Multiplying the two same variables will combine them into one variable of an even power. (odd number + odd number = even number)
Then the square root (even root/radicand) can be taken eliminating the radicand.
Here's an example to show you what I mean, so you can put it in your own words if you want.
[tex] \sqrt{ x^{3} } * \sqrt{ x^{7} } = \sqrt{ x^{10} } = x^{5} [/tex]