\[= a^{2} - 8a + 16 =\]
\[= (a - 4)^{2} \geq 0 - при\ любом\ \]
\[значении\ переменной\ a.\]
\[x_{1} = \frac{- (2 - 5a) - (a - 4)}{2} =\]
\[= \frac{4a + 2}{2} = 2a + 1;\]
\[x_{2} = \frac{- (2 - 5a) + (a - 4)}{2} =\]
\[= \frac{6a - 6}{2} = 3a - 3.\]
\[\left( x - x_{1} \right)\left( x - x_{2} \right) < 0\]
\[x_{1} < x < x_{2}.\]
\[Сравним\ корни:\]
\[2a + 1 > 3a - 3\]
\[a < 4.\]
\[При\ a < 4:\]
\[3a - 3 < x < 2a + 1.\]
\[При\ a = 4:\]
\[x \in \varnothing.\]
\[При\ a > 4:\]
\[2a + 1 < x < 3a - 3.\]