Đáp án: $<=>\left[\begin{array}{l} x=0;y=-3\\x=3;y=0\end{array} \right.$
Giải thích các bước giải: $ \left\{\begin{array}{l} xy-x+y= -3\\ x^2+y^2-x+y+xy=6\end{array} \right.\\ <=>\left\{\begin{array}{l} xy-x+y= -3\\ x^2+y^2= 9\end{array} \right.\\ <=>\left\{\begin{array}{l} xy-x+y= -3\\ x^2+y^2-2(xy-x+y)= 9-2.(-3)\end{array} \right.\\ <=>\left\{\begin{array}{l} xy-x+y= -3\\ (x-y)^2+2(x-y)= 15\end{array} \right.\\ <=>\left\{\begin{array}{l} xy-(x-y)= -3\\ \left[\begin{array}{l} x-y=3\\x-y=-5 \end{array} \right.\end{array} \right.\\ <=>\left[\begin{array}{l} \left\{\begin{array}{l} xy=0 \\x-y=3 \end{array} \right.\\ \left\{\begin{array}{l} xy=-8\\x-y=-5 \end{array} \right.\end{array} \right.\\ <=>\left[\begin{array}{l} x=0;y=-3\\x=3;y=0\end{array} \right.$
