Question

simplifique as expressões abaixo

Answer 1

Usando as propriedades do fatorial:
a)
$\frac{(n-4)!}{(n-3)!}=\frac{(n-4)!}{(n-3).(n-4)!}$
$\frac{(n-4)!}{(n-3).(n-4)!}=\frac{1}{n-3}$

b)
$\frac{(2n)!}{(2n-2)!}= \frac{2n.(2n-1).(2n-2)!}{(2n-2)!}$
$\frac{2n.(2n-1).(2n-2)!}{(2n-2)!}=2n.(2n-1)$
$2n.(2n-1)=4n^{2}-2n$