Question 1066617
So, I'm assuming that P represents the permutation function.

If this is the case, then remember that the formula for P(n,r) = {{{n!/(n-r)!}}} 

So, substituting r = n-2 gives us:   {{{n!/(n-(n-2))!}}}

But n - (n-2)  = 2.

So the answer is simply  {{{n!/2!}}} =  {{{n!/4}}}