9.035. $\frac{4 x^{2}-1}{\log _{1.7}\left(\frac{1}{2}\left(1-\log _{7} 3\right)\right)} \leq 0$.
Solution.

$\log _{1.7}\left(\frac{1}{2}\left(1-\log _{7} 3\right)\right)<0$, so the original inequality is equivalent to the following: $4 x^{2}-1 \geq 0$. Solving it, we find $x \geq \frac{1}{2}$ or $x \leq-\frac{1}{2}$.

Answer: $\quad x \in\left(-\infty ;-\frac{1}{2}\right] \cup\left[\frac{1}{2} ; \infty\right)$