# How do you evaluate log_(1/9) (1/81)?

${\log}_{\frac{1}{9}} \left(\frac{1}{81}\right) = 2$
As ${\left(\frac{1}{9}\right)}^{2} = \frac{1}{81}$,
by the definition of logarithm that $\mathmr{if} {a}^{b} = m$, then ${\log}_{a} m = b$, we get
${\log}_{\frac{1}{9}} \left(\frac{1}{81}\right) = 2$