Answer
$log_{5}(y^{4}-7y)$
Work Step by Step
The product property of logarithms tells us that $log_{b}xy=log_{b}x+log_{b}y$ (where x, y, and, b are positive real numbers and $b\ne1$).
Therefore, $log_{5}y^{3}+log_{5}(y-7)= log_{5}(y^{3}\times(y-7))=log_{5}(y^{4}-7y)$.
