Ok, first factor the denominators of both fractions. They come out to be "x(x-5)" and "(x-5)(x+3)" Then you look to see what they have in common. In this case they have "(x-5)" in common. Because of this, that automatically goes in the denominator. Then in addition to what they have in common, you multiply that by what they don't have in common. The answer comes out to be "x(x-5)(x+3)" Basically, you combine what they have in common and what they don't have in common together.