\[- 3x^{2} + 7x + 6 < 0\]
\[D = 49 + 72 = 121\]
\[x_{1} = \frac{- 7 + 11}{- 6} = - \frac{2}{3}\]
\[x_{2} = \frac{- 7 - 11}{- 6} = 3\]
\[Ответ:\left( - \infty;\ - \frac{2}{3} \right) \cup (3;\ + \infty).\]