So we have the square root of x plus 4 minus 3 over x minus 5. And any time you see a radical plus or minus something else, to get rid of the radical what you can do is multiply by the radical doing the, or if you have a radical minus 3 you multiply by the radical plus 3. So in this situation you just multiply the numerator by square root of x plus 4 plus 3 over the square root of x plus 4 plus 3. We obviously have to multiply the numerator and the denominator by the same thing so that we actually don't change the value of the expression. If this right over here had a plus 3 then we would do a minus 3 here. This is a technique that we learn in algebra or sometimes in pre-calculus class to rationalize usually denominators but to rationalize numerators or denominators. It's also a very similar technique that we use oftentimes to get rid of complex numbers usually in denominators.