Question

can someone explain the following:

Answer 1

\[(n+4)!\div4n! + (n+4)!\div(n+1)! = (n+1)(n+4)!+4(n+4)!\div4(n+1)!\]

Answer 2

do you know what a factorial is?
ie 3! is 3*2*1
I think (n+4)! is (n+4)(n+3)(n+2)(n+1)n