square of u - square root of v/ square root of u + square root of v.

Answer 1

that makes no sense

Answer 2

It appears you want to rationalize the fraction. So, multiply top and bottom by

sqrt(u)-sqrt(v)

That gives you
(sqrt(u)-sqrt(v))^2/(u-v)
= (u - 2sqrt(uv) + v)/(u-v)