You can put this solution on YOUR website! Please put radicands in parentheses. ("Radicand" is the name for the expression inside a radical.) The way you've posted this I cannot tell if the 15 is inside or outside the radical. Without any parentheses what you posted means:
but I suspect that you meant:
which should be posted as something like:
5 + square root(x+15) = x
Not knowing which equation is correct, I choose not to risk wasting my time in solving the wrong equation. Please re-post your question using parentheses around the radicand (even if it is just x).