\[\left\{ \begin{matrix} 2x + 5 \geq x + 7\ \ \\ 3x - 4 \leq 2x + 4 \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} x \geq 2 \\ x \leq 8 \\ \end{matrix} \right.\ \]
\[x = 2\ (наим);x = 8\ (наиб);\]
\[2^{2} + 2 \cdot 8 = 4 + 16 = 20.\]
\[Ответ:20.\]