\[x² - 2x - 15 = 0\]
\[x_{1} + x_{2} = 2\]
\[x_{1} \cdot x_{2} = - 15 \Longrightarrow x_{1} = 5;\ \ \]
\[x_{2} = - 3\]
\[Ответ:x_{1} = 5;\ \ x_{2} = - 3.\]