Find \(n\) if \(n\cdot n! + n! = 720\), where \(n! = n\cdot (n-1)\cdot (n-2)\cdots 2\cdot 1\).
I got the answer
n * n! + n! = 720
Note that if n = 5 then
5 * 5! + 5! =
5 (120) + 120 =
600 + 120 =
720 !!!
