Major Math Graphing Assignment

I have to graph this function as part of my math assignment for calculus.

f(x) =__ x2 (supposed to be x squared) - 2x - 15__

x + 3

** it's x squared minus 2x minus 15 all over x+3

i know that it is a straight line with a whole in it at x= -3. However, i just want to make sure i have all the steps correct in coming up with this answer. And even though it's a straight line, i need to determine f'(x) and f''(x) to find critical points and intervals of concavity and inflection point.

Any help at all would be much appreciated.. thank-you very much