Answer
$3-log_{5}y$
Work Step by Step
Based on the quotient rule of logarithms, we know that $log_{b}(\frac{M}{N})=log_{b}M-log_{b}N$ (where $b$, $M$, and $N$ are positive real numbers and $b\ne1$).
Therefore, $log_{5}(\frac{125}{y})=log_{5}125-log_{5}y$.
Based on the definition of the logarithmic function, we know that $y=log_{b}x$ is equivalent to $b^{y}=x$ (for $x\gt0$ and $b\gt0$, $b\ne1$).
Therefore, $log_{5}125=3$, because $5^{3}=125$. So, $log_{5}125-log_{5}y=3-log_{5}y$.
