\[\sqrt{1 - \frac{1}{16}x²} + \sqrt{x^{2} - 9}\]
\[\left\{ \begin{matrix} (x + 4)(x - 4) \leq 0 \\ (x + 3)(x - 3) \leq 0 \\ \end{matrix} \right.\ \]
\[D(y) = \lbrack - 4; - 3\rbrack \cup \lbrack 3;4\rbrack.\]