Решить систему уравнений {x+xy+y=-3 {x-xy+y=1

  { x+xy+y=_-  3                                                                   {x(1+y)+y=_-3 {x(1-y)+y=1 {x(1+y)+y=-3 {x(1-y)=1-y |: 1-y не равно нулю, у не равен 1.   {x(1+y)+y=-3                                             при у=1 {х+х+1=-3 {x=1                                                                      {x-x+1=1   1+y+y=-3                                                              {2x=-4 2y=-3-1                                                                 {0x=0 2y=-4 y=-4:2                                                                   x=2 y=2                                                       x-любое ответ: (1;2), (2;1)