\[\sqrt{7x - 9} - \frac{3}{x^{2} - 16}\]
\[\left\{ \begin{matrix}
7x - 9 \geq 0 \\
x
eq \pm 4\ \ \ \ \ \ \ \\
\end{matrix} \right.\ \text{\ \ \ \ \ }\]
\[\left\{ \begin{matrix}
7x \geq 9\ \\
x
eq \pm 4 \\
\end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix}
x \geq 1\frac{2}{7} \\
x
eq \pm 4\ \\
\end{matrix} \right.\ \]
\[Ответ:\ \left\lbrack 1\frac{2}{7};4 \right) \cup (4; + \infty).\]