решите пожалуйста срочно

   3(x + y) + 1 = x + 4y           3x + 3y + 1 = x + 4y          3x +3y - x - 4y = -1
 {                                          {                                         {
   7 - 2(x - y) = x - 8y               7 - 2x +2y  = x - 8y           2y - 2x - x + 8y = -7
    2x -y = - 1                   20x - 10y = -10
  {                               +{
    -3x + 10y = -7             -3x + 10y = -7          20x -3x = -17     17x = -17           x = -1
  Подставляя в первое уравнение  2x - y = -1 получаем  2* -1 - у = - 1
-2 - 1 - у = - 1         -у = -1 + 3        -у = 2     у = - 2
Ответ :  x = - 1          y = - 2