\[\boxed{\mathbf{51.}}\]
\[y = x^{2} + bx + c;\ \ x \in ( - 4;\ - 2).\]
\[Нули\ функции:\]
\[x = - 4;\ \ x = - 2.\]
\[x = - 4:\]
\[y = 16 - 4b + c;\]
\[x = - 2:\]
\[y = 4 - 2b + c.\]
\[\left\{ \begin{matrix} 16 - 4b + c = 0\ \ \ \ \ \ \ \\ 4 - 2b + c = 0\ \ \ \ \ \ \ \ \ \\ \end{matrix} \right.\ ( - )\]
\[12 - 2b = 0\]
\[2b = 12\]
\[b = 6.\]
\[4 - 2b + c = 4 - 2 \cdot 6 + c =\]
\[= - 8 + c\]
\[- 8 + c = 0\]
\[c = 8.\]
\[Ответ:при\ b = 6;\ \ c = 8.\]