Question

Qual a solução? por favor.

n!
--------- = 42
(n - 2)!​

Answer 1

Resposta:

n=4

Explicação passo-a-passo:

$\frac{n!}{(n-2)!}=42\\\\\frac{n(n-1)(n-2)!}{(n-2)!}=42\\\\n(n-1)-42=0\\\\n^2-n-42=0\\\\D=(-1)^2-4.1)-42)\\\\D=1+48\\\\D=49\\\\n=\frac{-(-1)-7}{2.1}\\\\n=\frac{1-7}{2}=-3\:nao\:serve\\\\n=\frac{-(-1)+7}{2.1}=\frac{8}{2}=4$