\[ax² - x + 2\]
\[D = 1 - 8a\]
\[1 - 8a \geq 0\]
\[8a \leq 1\]
\[a \leq \frac{1}{8}\]
\[Ответ:\left( - \infty;\frac{1}{8} \right\rbrack.\]