Решите систему уравнений: y-7x=3; y^2-6xy-x^2=-9.

\[\left\{ \begin{matrix} y - 7x = 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ y^{2} - 6xy - x^{2} = - 9 \\ \end{matrix}\text{\ \ \ \ \ \ } \right.\ \]

\[6x^{2} + 24x + 18 = 0\ \ \ \ \ \ \ \ \ \ \ |\ :6\]

\[x^{2} + 4x + 3 = 0\ \ \]

\[x_{1} + x_{2} = - 4,\ \ x_{1} \cdot x_{2} = 3\ \]

\[x = - 3,\ \ x = - 1\]

\[\left\{ \begin{matrix} x = - 3\ \ \\ y = - 18 \\ \end{matrix}\text{\ \ \ \ \ } \right.\ \text{\ \ \ \ \ \ \ \ \ }\left\{ \begin{matrix} x = - 1 \\ y = - 4 \\ \end{matrix} \right.\ \]

\[Ответ:( - 3;\ - 18);\ ( - 1;\ - 4).\]