\[f(x) = \left\{ \begin{matrix} - \frac{8}{x};\ \ \ \ \ \ \ \ \ \ x < - 2 \\ - 2x;\ - 2 \leq x \leq 2 \\ - \frac{8}{x};\ \ \ \ \ \ \ \ \ \ \ \ \ \ x > 2 \\ \end{matrix} \right.\ \]
\[D(f) = \lbrack - 2;2\rbrack;\]
\[E(f) = \lbrack - 4;4\rbrack.\]
\[f(x) > 0\ при\ x < 0;\ \]
\[f(x) < 0\ при\ x > 0;\]
\[f(x) = 0\ при\ x = 0.\]
\[f(x)\ возрастает\ при\ \]
\[x \in ( - \infty;\ - 2) \cup (2; + \infty);\]
\[f(x)\ убывает\ при\ x \in \lbrack - 2;2\rbrack.\]