Question

calcule n sabendo que
n!/(n-2)!=30

Answer 1

n!/(n-2)!=30
n(n-1)!/(n-2)! = 30
n(n-1)(n-2)! / (n-2)! = 30
n(n-1) = 30
n^2 -n -30 = 0

n = (1 +- √1 + 120)/2
n = (1 +- 11)/2
n' = 6
n" = -5