To square root something, in a way is to find the one number when multiplied by it self is equal to your starting number, for example the square root of 64 would be 8 since 8x8 is 64.
So if you are squaring the square root, the equation "simplified" would end up being 2+3.
(sqrt of 2 + sqrt of 3)2
the ^2 negates the square roots of 2 and three leaving you with 2+3 in the brackets.
So your answer would be 5