\[y = x^{2} - 2x - 3;\ \ \lbrack 0;3\rbrack.\]
\[Парабола,\ ветви\ вверх,\ найдем\ \]
\[координаты\ вершины:\]
\[x_{0} = - \frac{b}{2a} = \frac{2}{2} = 1;\ \ \ \ \]
\[y_{0} = 1 - 2 - 3 = - 4.\]
\[y(0) = - 3;\ \]
\[y(3) = 9 - 6 - 3 = 0.\]
\[E(y) = \lbrack - 4;0\rbrack.\]