#### Answer

$log_{15}x=2$

#### Work Step by Step

From the definition of the logarithmic function on page 456, we know that $b^{y}=x$ is equivalent to $y=log_{b}x$ (for $x\gt0$, $b\gt0$, and $b\ne1$).
Therefore, $15^{2}=x$ is equivalent to $log_{15}x=2$ in logarithmic form.