1. $\left\{\begin{matrix} x^2+y^2-4x+2y=-3 & \\ x^2+y^2-xy+x-2y=12 & \end{matrix}\right.$
2. $\left\{\begin{matrix} x^2+y^2=8-x-y & \\ xy(x+y+xy+1)=12 & \end{matrix}\right.$
3. $\left\{\begin{matrix} x^4+y^4+6x^2y^2=41 & \\ xy(x^2+y^2)=10 & \end{matrix}\right.$