\[\boxed{\mathbf{623}.}\]
\[1)\ \left\{ \begin{matrix} 3 - x \leq 2\ \ \\ 2x + 1 \leq 4 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ }\left\{ \begin{matrix} - x \leq - 1 \\ 2x \leq 3\ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\ \left\{ \begin{matrix} x \geq 1\ \ \ \\ x \leq 1,5 \\ \end{matrix} \right.\ ;\]
\[Ответ:\ \ 1 \leq x \leq 1,5.\]
\[2)\ \left\{ \begin{matrix} x^{2} - 1 \geq 0 \\ x > 2\ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} (x + 1)(x - 1) \geq 0 \\ x > 2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\ \left\{ \begin{matrix} x \leq - 1\ и\ x \geq 1 \\ x > 2\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ ;\]
\[Ответ:\ \ x > 2.\]
\[3)\ \left\{ \begin{matrix} 9 - x^{2} \leq 0 \\ x + 5 < 0\ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\ \left\{ \begin{matrix} (x + 3)(x - 3) \geq 0 \\ x < - 5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\ \left\{ \begin{matrix} x \leq - 3\ и\ x \geq 3 \\ x < - 5\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ ;\]
\[Ответ:\ \ x < - 5.\]