Question

Решите систему уравнений:
3x-y=-9
x+2y=11

Answer 1

{3x-y=-9        {-y=-9-3x           {y=9+3x              {y=9+3x            {y=9+3x

                  :                       :                            ;                        :

{x+2y=11      {x+2y=11          {x+2(9+3x)=11    {x+18+6x=11    {7x=-9

{y=9+3x    { y≈9+3.9    {y≈12.9

               ;                  ;

{x≈1.3       {x≈1.3         {x≈1.3