Question 924384
(n+2)! / n! is equal to:


(n+2) * (n+1) * n! / n! which is equal to n+2 * n+1


an example will help clarify the concept.


assume n = 6


n+2 must be equal to 8


(n+2)! = 8*7*6*5*4*3*2*1


n! = 6*5*4*3*2*1


since 6*5*4*3*2*1 = 6!, you get:


8! = 8*7*6!


8! / 6! = 8*7*6! / 6! = 8*7 = 56