\[f(x) = x^{2} - 4x + 3 \Longrightarrow ветви\ \]
\[вверх;\]
\[x_{0} = \frac{4}{2} = 2;\ \ \]
\[y_{0} = 4 - 8 + 3 = - 1\]
\[E(f) = \lbrack - 1; + \infty).\]