\[\left\{ \begin{matrix}
3x + 12 < - 3 \\
11 - 5x > 26\ \\
\end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix}
3x < - 15 \\
- 5x > 15 \\
\end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix}
x < - 5 \\
x < - 3 \\
\end{matrix} \right.\ \text{\ \ }\]
\[Ответ:\ x \in ( - \infty;\ - 5).\]