Question

Simplifique a expressão (n+2)!(n-1)!/n!(n+1)!=2
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Answer 1

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

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

$\frac{(n+2)}{n}=2$

$n+2=2n$

$2=2n-n$

$2=n$

$\boxed{n=2}$