Discussion in 'Math' started by boks, Dec 6, 2009.
Why is it that
The key is to multiply through by 2! This will enable you to get rid of all the factorials and the rest is simple algebra.
Can you do it now?
I just substituted X!/(X)(X-1) for (X-2)! and everything canceled out to give the answer.
From the definition of factorial, X!, you write out X! as X(X-1)(X-2)(X-3)(X-4)... and (X-2)! as (X-2)(X-3)(X-4)..., simplification becomes much easier.