First of all, we know that X and Y must be of the same sign, so X and Y are the same positive or negative.

Then, because the root sign must be non-negative, but because the square of X is definitely non-negative, and there is a negative sign in the root sign, it means that Y is definitely negative, and because X and Y are of the same sign, X is also negative.

If you want to put a negative number in the root sign, you must add a negative sign outside the root sign, so it becomes: negative Y below the negative root sign.