\[\frac{5y + 20}{y^{2} - 16y + 64} \cdot \frac{6y - 48}{y + 4} =\]
\[= \frac{5 \cdot (y + 4) \cdot 6 \cdot (y - 8)}{(y - 8)^{2}(y + 4)} =\]
\[= \frac{30}{y - 8}.\]