\[y = - 2x^{2} - (2a - 1)x + 3a + 2\]
\[Пусть\ \ x_{1} < 2 < x_{2};\ \]
\[- 2 < 0;\ \ \ \ f(2) > 0.\]
\[= - 8 - 4a + 2 + 3a + 2 =\]
\[= - a - 4\]
\[- a - 4 > 0\]
\[- a > 4\]
\[\ \ a < - 4.\]
\[Ответ:\ при\ a < - 4.\]