Hey, I was wondering if someone could help me with a specific type of question that I can't seem to understand without an answer key. Anyway, it's rewriting expressions with factorial notation so that they no longer have factorial symbols. Example: Simplify without using the factorial symbol: (n-2)!(n+1)!/(n!)² The answer is: n+1/n(n-1) What I don't understand is how you come to that conclusion. Can someone explain this to me?