\[\boxed{\mathbf{229}\mathbf{.}}\]
\[1)\ 5^{x - 1} \leq \sqrt{5}\]
\[5^{x - 1} \leq 5^{\frac{1}{2}}\]
\[x - 1 \leq \frac{1}{2}\]
\[x - 1 \leq 0,5\ \]
\[x \leq 1,5\]
\[Ответ:\ \ x \leq 1,5.\]
\[2)\ 3^{\frac{x}{2}} > 9\]
\[3^{\frac{x}{2}} > 3^{2}\]
\[\frac{x}{2} > 2\]
\[x > 4\]
\[Ответ:\ \ x > 4.\]
\[3)\ 3^{x^{2} - 4} \geq 1\]
\[3^{x^{2} - 4} \geq 3^{0}\]
\[x^{2} - 4 \geq 0\]
\[(x + 2)(x - 2) \geq 0\]
\[x \leq - 2;\ \ \text{\ \ }x \geq 2.\]
\[Ответ:\ \ x \leq - 2;\ \ \ x \geq 2.\]
\[4)\ 5^{2x^{2} - 18} < 1\]
\[5^{2x^{2} - 18} < 5^{0}\]
\[2x^{2} - 18 < 0\]
\[x^{2} - 9 < 0\]
\[(x + 3)(x - 3) < 0\]
\[- 3 < x < 3\]
\[Ответ:\ \ - 3 < x < 3.\]