You apparently know how to solve equations with 
square roots. You only need to learn how to check 
your answers. You must always check answers in 
equations containing square roots, for they often
give bogus solutions.



Let's check your first answer x=-5







That has a neative number under a square root,
so it cannot be a real number. So -5 is an
extraneous solution.  So we discard it.



Let's check your second answer x=4











That one checks.  So x = 4 is the only
solution.

Edwin