\[- 100c^{2} + 20c + 3 = 0\]
\[100c^{2} - 20c - 3 = 0\]
\[D = 100 + 300 = 400\]
\[c_{1} = \frac{10 + 20}{100} = \frac{30}{100} = \frac{3}{10} = 0,3;\]
\[c_{2} = \frac{10 - 20}{100} = - \frac{10}{100} = - 0,1.\]