Answer
$5^{y}=125$
Work Step by Step
From the definition of the logarithmic function on page 456, we know that $y=log_b{x}$ is equivalent to $b^{y}=x$ (for $x\gt0$, $b\gt0$, and $b\ne1$).
Therefore, $y=log_5{125}$ is equivalent to $5^{y}=125$ in exponential form.