Решите систему уравнений: x+2y=1; 2x+y^2=-1.

\[2 - 4y + y^{2} + 1 = 0\]

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

\[D_{1} = 4 - 3 = 1\]

\[y_{1} = 2 + 1 = 3;\ \ \]

\[y_{2} = 2 - 1 = 1.\]

\[\left\{ \begin{matrix}
y = 3\ \ \\
x = - 5 \\
\end{matrix} \right.\ \ \ \ \ или\ \ \ \ \left\{ \begin{matrix}
y = 1\ \ \ \\
x = - 1 \\
\end{matrix} \right.\ \]

\[Ответ:( - 5;3);\ \ ( - 1;1).\]