\[10n² - 9n + 2 = 0\]
\[D = ( - 9)^{2} - 4 \cdot 10 \cdot 2 =\]
\[= 81 - 80 = 1\]
\[n_{1} = \frac{9 + \sqrt{1}}{2 \cdot 10} = \frac{9 + 1}{20} = \frac{10}{20} =\]
\[= \frac{1}{2} = 0,5;\]
\[n_{2} = \frac{9 - \sqrt{1}}{2 \cdot 10} = \frac{9 - 1}{20} = \frac{8}{20} =\]
\[= \frac{2}{5} = 0,4.\]
\[Ответ:x = 0,5;x = 0,4.\ \]