Simplify the sum. d^2-9d+20/d^2-3d-10 plus d^2-2d-8/d^2+4d-32

For this case what you should do is follow the following steps:
 1) factorize numerator and denominator of both expressions.
 2) cancel similar terms
 3) add both fractions by cross product
 4) Rewrite the numerator and denominator.
 Answer:
 See attached image.