Answer
{$\frac{3}{4}$}
Work Step by Step
For all positive numbers $a$, where $a\ne1$, and all positive numbers $x$, we know that $y=log_{a}x$ means the same as $x=a^{y}$.
Therefore, $log_{81}27=x$ means the same as $81^{x}=27$.
We know that $x=\frac{3}{4}$, because $81^{\frac{3}{4}}=27$.
