5?
\[x^{2} - (a + 1)x - 2a^{2} - a = 0\]
\[= a^{2} + 2a + 1 + 8a^{2} + 4a =\]
\[= 9a^{2} + 6a + 1 = (3a + 1)^{2};\ \ \ \ \]
\[= a \neq - \frac{1}{3}\]
\[x_{1} = \frac{a + 1 + 3a + 1}{2} = \frac{4a + 2}{2} =\]
\[= 2a + 1\]
\[x_{2} = \frac{a + 1 - 3a - 1}{2} =\]
\[= - \frac{2a}{2} = - a\]
\[\left\{ \begin{matrix} 2a + 1 < 5 \\ - a < 5\ \ \ \ \ \ \ \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} 2a < 4\ \\ a > - 5 \\ \end{matrix} \right.\ \text{\ \ \ \ \ \ \ }\]
\[\left\{ \begin{matrix} a < 2\ \ \ \\ a > - 5 \\ \end{matrix} \right.\ \]
\[Ответ:\left( - 5;\ - \frac{1}{3} \right) \cup \left( - \frac{1}{3};2 \right).\]