Question

Calcule o valor de x:

$log_{x} ( \frac{1}{81})=-2$

Answer 1

$log_x ( \frac{1}{81} )=-2\\ \\ \frac{1}{81}=x^{-2}\\ \\ (\frac{1}{9})^2=x^{-2}\\ \\ 9^{-2}=x^{-2}\\ x = 9$