You can
put this solution on YOUR website!The notation

tells you to simply multiply that number by every integer that is less than that number until you hit 1. So if

, this means that

.
In this case,
which simplifies to
and
So

Highlight the common terms.

Cancel out the common terms.
!}{(2n)!}=(2n+2)(2n+1))
Simplify.
!}{(2n)!}=4n^2+6n+2)
FOIL

to get