\[1)\ |2x - 5| \leq 3\]
\[- 3 \leq 2x - 5 \leq 3\]
\[2 \leq 2x \leq 8\]
\[1 \leq x \leq 4.\]
\[Ответ:\ \ x \in \lbrack 1;\ 4\rbrack.\]
\[2)\ |5x - 9| > 4\]
\[5x - 9 < - 4\]
\[5x < 5\]
\[x < 1.\ \]
\[5x - 9 > 4\]
\[5x > 13\]
\[x > 2,6.\]
\[Ответ:\ \ \]
\[x \in ( - \infty;\ 1) \cup (2,6;\ + \infty).\]
\[3)\ |2 - 3x| < x + 1\]
\[2 - 3x > - x - 1\]
\[2x < 3\]
\[x < 1,5.\]
\[2 - 3x < x + 1\]
\[4x > 1\]
\[x > 0,25.\]
\[Ответ:\ \ x \in (0,25;\ 1,5).\]
\[4)\ |1 + 2x| \geq 3 - x\]
\[1 + 2x \leq - 3 + x\]
\[2x - x \leq - 4\ \ \ \]
\[x \leq - 4.\]
\[1 + 2x \geq 3 - x\]
\[3x \geq 2\]
\[x \geq \frac{2}{3}.\]
\[Ответ:\ \ \]
\[x \in ( - \infty;\ - 4\rbrack \cup \left\lbrack \frac{2}{3};\ + \infty \right).\]