\[15x² - 16x - 15 = 0\]
\[D = 256 + 900 = 1156\]
\[x_{1,2} = \frac{16 \pm 34}{30}\]
\[x_{1} = \frac{5}{3} = 1\frac{2}{3};\ \ \ x_{2} = - \frac{3}{5} = - 0,6\]
\[Ответ:1\frac{2}{3};\ \ - 0,6.\]