\[ax² - 3x + 3\]
\[ax^{2} - 3x + 3 = 0\]
\[D \geq 0:\]
\[D = 9 - 4 \cdot a \cdot 3 = 9 - 12a\]
\[9 - 12a \geq 0\]
\[12a \leq 9\]
\[a \leq \frac{3}{4}\]
\[a \leq 0,75\]
\[Ответ:\ ( - \infty;\ 0,75\rbrack.\]