\[\left( \frac{3^{\backslash y + 2}}{y - 2} - \frac{3^{\backslash y - 2}}{y + 2} \right) \cdot \frac{y^{2} - 4}{y + 4} =\]
\[= \frac{3y + 6 - 3y + 6}{(y - 2)(y + 2)} \cdot \frac{(y - 2)(y + 2)}{y + 4} =\]
\[= \frac{12}{y + 4}\]