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