\[3x^{2} - 8x - 11 = 0\]
\[D = ( - 8)^{2} - 4 \cdot 3 \cdot ( - 11) =\]
\[= 64 + 132 = 196\]
\[x_{1} = \frac{8 + \sqrt{196}}{2 \cdot 3} = \frac{8 + 14}{6} = \frac{22}{6} =\]
\[= \frac{11}{3} = 3\frac{2}{3}\]
\[x_{2} = \frac{8 - \sqrt{196}}{2 \cdot 3} = \frac{8 - 14}{6} = \frac{- 6}{6} =\]
\[= - 1\]
\[Ответ:x = 3\frac{2}{3};\ x = - 1.\]