Question

resolva a equação:
x! / (x-2) ! = 30

Answer 1

$\frac{x!}{(x-2)!} =30 \\ \\ \frac{x(x-1)(x-2)!}{(x-2)!}=30 \\ \\ x(x-1)=30 \\ \\ x^{2}-x = 30 \\ \\ x^{2}-x - 30 = 0 \\ \\ D = (-1)^{2}-4(1)(-30) = 1 + 120 = 121 \\ \\ \sqrt{D} = \sqrt{121} = 11 \\ \\ x' = \frac{1 + 11}{2} = \frac{12}{2} = 6 \\ \\ x'' = \frac{1-11}{2} = \frac{-10}{2} = -5 (n)$

Resposta x = 6

Espero ter ajudado.