x^2 + y^2 +x +3y =8
xy + x + y = 1


mong ae giải giúp cái
\[\begin{array}{l}
\left\{ \begin{array}{l}
a = x + \frac{1}{2}\\
b = y + \frac{3}{2}
\end{array} \right.\\
\left\{ \begin{array}{l}
{a^2} + {b^2} = \frac{{11}}{2}\\
2ab - a + b = \frac{9}{4}
\end{array} \right.\\
\to {a^2} - 2ab + {b^2} + a - b = \frac{{11}}{2} - \frac{9}{4}\\
\to ...
\end{array}\]