Resposta :

[tex]\frac{n!}{(n - 1)!} + \frac{(n - 1)!}{(n - 2)!} = 11 \\\\ \frac{n(n - 1)!}{(n - 1)!} + \frac{(n - 1)(n - 2)!}{(n - 2)!} = 11 \\\\ \frac{n}{1} + \frac{(n - 1)}{1} = 11 \\ n + n - 1 = 11 \\ 2n = 12 \\ \boxed{n = 6}[/tex]

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