\[\boxed{\mathbf{957\ (957).\ }Еуроки\ - \ ДЗ\ без\ мороки}\]
\[x^{2} - (2a + 2)x - 2a - 3 = 0\ \ \]
\[x_{1} < 0;\ \ x_{2} < 0\]
\[\left\{ \begin{matrix} x_{1} + x_{2} = 2a + 2 \\ x_{1}x_{2} = - 2a - 3 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\ \left\{ \begin{matrix} - 2a - 3 > 0 \\ 2a + 2 < 0 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} - 2a > 3 \\ 2a < - 2 \\ \end{matrix} \right.\ \text{\ \ \ \ }\]
\[\text{\ \ }\left\{ \begin{matrix} a < - 1,5 \\ a < - 1\ \ \ \\ \end{matrix} \right.\ \Longrightarrow \ \ a < - 1,5\]
\[Ответ:( - \infty;\ - 1,5).\]