\[f(x) = x^{2} + 4x - 16 \Longrightarrow \ ветви\ \]
\[вверх.\]
\[x_{0} = \frac{- 4}{2} = - 2\]
\[y_{0} = 4 - 8 - 16 = - 20 \Longrightarrow\]
\[\Longrightarrow ( - 2;\ - 20)\text{.\ }\]
\[E(f) = \lbrack - 20;\ + \infty)\]
\[убывает\ на\ ( - \infty;\ - 2\rbrack\]
\[возрастает\ на\ \lbrack - 2;\ + \infty).\]