\[f(x) = 2x^{2} - 8x + 1 \Longrightarrow ветви\ \]
\[вверх;\]
\[x_{0} = \frac{8}{4} = 2;\ \ y_{0} = 8 - 16 + 1 =\]
\[= - 7 \Longrightarrow (2; - 7)\]
\[E(f) = \lbrack - 7; + \infty) \Longrightarrow убывает\ \]
\[на\ ( - \infty;2\rbrack;\ \ \]
\[возрастает\ на\ \lbrack 2; + \infty)\text{.\ }\]