\[f(x) = \sqrt{x - 9\ } + \frac{6}{\sqrt{8 - x\ }\ }\text{\ \ \ \ \ }\]
\[\left\{ \begin{matrix} x - 9 \geq 0 \\ 8 - x > 0 \\ \end{matrix}\text{\ \ \ \ \ } \right.\ \left\{ \begin{matrix} x \geq 9 \\ x < 8 \\ \end{matrix} \right.\ \]
\[\Longrightarrow нет\ таких\ значений.\]