Решим неравенство:
\(9x^2 - 20x + 4 \ge 0\)
\[D = (-20)^2 - 4 \cdot 9 \cdot 4 = 400 - 144 = 256\]
\[x_1 = \frac{20 + \sqrt{256}}{2 \cdot 9} = \frac{20 + 16}{18} = \frac{36}{18} = 2\]
\[x_2 = \frac{20 - \sqrt{256}}{2 \cdot 9} = \frac{20 - 16}{18} = \frac{4}{18} = \frac{2}{9}\]
+ - +
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2/9 2
Ответ: \(x \in (-\infty; \frac{2}{9}] \cup [2; +\infty)\)