\[- 50a^{2} + 5a + 1 = 0\ \ \ \ | \cdot ( - 1)\]
\[50a^{2} - 5a - 1 = 0\]
\[D = 25 + 200 = 225\]
\[a_{1} = \frac{5 + 15}{100} = \frac{20}{100} = 0,2;\ \ \ \]
\[a_{2} = \frac{5 - 15}{100} = - \frac{10}{100} = - 0,1\]
\[Ответ:a = - 0,1;\ \ a = 0,2.\]