Question

resolva a equação A x;2=30

Answer 1

$A_x_,_2 = 30\\\\ \frac{x!}{(x-2)!} = 30\\\\\ \frac{x(x-1)(x-2)!}{(x-2)!} = 30\\\\\ x^2-x-30 = 0\\\\\ \Delta = 121\\\\\ x^1 = 6\\\\ x^2 = -5$

Solução : -5 e 6