\[y = 3x^{2} - 6x + c\]
\[y_{наим} = - 2;\]
\[ветви\ вверх;\ \ \ y_{наим} = y_{0}.\]
\[x_{0} = \frac{6}{6} = 1\]
\[3 - 6 + c = - 2\ \]
\[c = 1\]
\[Ответ:при\ c = 1.\]