Question

Por favor me ajudem!!!​

Answer 1

Resposta:

$\frac{n.n-1.n-2!}{n-2!} =n.n-1=n^{2} -n$

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