Question 246169
Hello, 
If we square each side then the square roots cancel.
[sqrt( x + 5)]^2 = [sqrt(x^2 - 15)]^2 reults in:
 x + 5 = x^2 - 15  Now move the x + 5 to the other side:
0=x^2-x-20  Now we can factor this to be:
0= (x-5)(x+4)This gives us:
x=5
x=-4
These can be put into the original problem. 
Does it work out?
RJ Toftness
Check out my book at www.math-unlock.com