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