Question

Calcular o valor de:
OBS: imagem em anexo

Answer 1

Resposta:

$\boxed{x=3}$

Explicação passo-a-passo:

$\boxed{P_x^{2}=C_{x,x-1}}\ \therefore\ \dfrac{x!}{2!}=\dfrac{x!}{(x-1)!(x-(x-1))!}\ \therefore$

$\dfrac{1}{2!}=\dfrac{1}{(x-1)!}\ \therefore\ (x-1)!=2!\ \therefore\ x-1=2\ \therefore\ \boxed{x=3}$