\[\left\{ \begin{matrix} x^{2} - 3x - 4 < 0 \\ 3x - 12 > 0\ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[x^{2} - 3x - 4 < 0\]
\[D = 9 + 16 = 25\]
\[x_{1} = \frac{3 + 5}{2} = 4;\]
\[x_{2} = \frac{3 - 5}{2} = - 1;\]
\[(x + 1)(x - 4) < 0\]
\[\left\{ \begin{matrix} (x + 1)(x - 4) < 0 \\ 3x > 12\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} - 1 < x < 4 \\ x > 4\ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\[нет\ решений.\]
\[Ответ:нет\ решений.\]