Question

(n+1)! x (n-2)! / (n)! x (n-1)!

Answer 1

$\frac{(n+1)!.(n-2)!}{n!.(n-1)!} = \frac{(n+1).n!.(n-2)!}{n!.(n-1).(n-2)!} = \frac{(n+1)}{(n-1)}$

Espero ter ajudado.