\[\frac{- 15}{5x + 6} < 0\]
\[- 15 < 0 \Longrightarrow 5x + 6 < 0 \Longrightarrow\]
\[\Longrightarrow x > - 1,2\]
\[\]
\[Ответ:( - 1,2; + \infty).\]