\[\ \left\{ \begin{matrix}
26 - x < 25 \\
2x + 7 < 13 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\left\{ \begin{matrix}
- x < - 1 \\
2x < 6\ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ }\left\{ \begin{matrix}
x > 1 \\
x < 3 \\
\end{matrix} \right.\ \]
\[\]
\[Ответ:x \in (1;3).\]
\[\left\{ \begin{matrix}
1 - 5x < 4 \cdot (1 - x) \\
3,5 + \frac{x}{4} \geq 2x\text{\ \ \ \ \ \ \ \ \ \ \ \ \ } \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
1 - 5x < 4 - 4x \\
3,5 \geq 2x - \frac{x}{4}\text{\ \ \ \ \ \ \ \ } \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
- x < 3\ \ \ \ \ \ \ \ \ \ \ \\
3,5 \geq 1,75x\ \\
\end{matrix} \right.\ \]
\[\left\{ \begin{matrix}
x > - 3 \\
x \leq 2\ \ \ \\
\end{matrix} \right.\ \]

\[\mathbf{Ответ}:x = - 2;\ - 1;0;1;2.\]
\[\sqrt{15 - 5m} + \sqrt{4 + m}\]
\[\left\{ \begin{matrix}
15 - 5m \geq 0 \\
4 + m \geq 0\ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ }\left\{ \begin{matrix}
- 5m \geq - 15 \\
m \geq - 4\ \ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
m \leq 3\ \ \ \ \\
m \geq - 4 \\
\end{matrix} \right.\ \]

\[Ответ:\ выражение\ имеет\ смысл\ при\ m \in \lbrack - 4;3\rbrack\text{.\ }\]
\[6x + 11 > \frac{b}{4}\text{\ \ \ \ \ \ }x \in (1; + \infty)\]
\[6x > \frac{b}{4} - 11\ \]
\[6x > \frac{b - 44}{4}\]
\[x > \frac{b - 44}{24}\]
\[1 < \frac{b - 44}{24} < + \infty\]
\[24 < b - 44 < + \infty\]
\[68 < b < + \infty\]
\[Ответ:b \in (68; + \infty).\]
\[\ 4^{11} \cdot 4^{- 9} = 4^{11 + ( - 9)} = 4^{2} = 16\]