Answer
$ \displaystyle \log_{3}(\frac{y}{4})$
Work Step by Step
$\displaystyle \log_{3}2y^{3}-\log_{3}8y^{2}=\qquad \color{blue}{\text{ ...apply } \log_{a}(\frac{x}{y})=\log_{a}x-\log_{a}y}$
$=\displaystyle \log_{3}(\frac{2y^{3}}{8y^{2}})$
$=\displaystyle \log_{3}(\frac{y}{4})$
