\[\frac{6y}{3y - 4} + \frac{15}{y + 6}\]
\[3y - 4 \neq 0\]
\[3y \neq 4\]
\[y \neq \frac{4}{3}.\]
\[y + 6 \neq 0\]
\[y \neq - 6.\]