Answer
$log_5{625}=4$
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, $5^{4}=625$ is equivalent to $log_5{625}=4$ in logarithmic form.