\[\boxed{\mathbf{704}.}\]
\[1)\ 5^{x - 1} \leq \sqrt{5};\]
\[5^{x - 1} \leq 5^{\frac{1}{2}};\]
\[x - 1 \leq \frac{1}{2};\]
\[x - 1 \leq 0,5;\ \]
\[x \leq 1,5;\]
\[Ответ:\ \ x \leq 1,5.\]
\[2)\ 3^{\frac{x}{2}} > 9;\]
\[3^{\frac{x}{2}} > 3^{2};\]
\[\frac{x}{2} > 2;\]
\[x > 4;\]
\[Ответ:\ \ x > 4.\]
\[3)\ 3^{x^{2} - 4} \geq 1;\]
\[3^{x^{2} - 4} \geq 3^{0};\]
\[x^{2} - 4 \geq 0;\]
\[(x + 2)(x - 2) \geq 0;\]
\[x \leq - 2\ \ и\ \ x \geq 2;\]
\[Ответ:\ \ x \leq - 2;\ \ x \geq 2.\]
\[4)\ 5^{2x^{2} - 18} < 1;\]
\[5^{2x^{2} - 18} < 5^{0};\]
\[2x^{2} - 18 < 0;\]
\[x^{2} - 9 < 0;\]
\[(x + 3)(x - 3) < 0;\]
\[- 3 < x < 3;\]
\[Ответ:\ \ - 3 < x < 3.\]