Respostas

  • Usuário do Brainly
2014-06-05T15:03:53-03:00


Podemos cancelar o y ,

somando 2x+6x =7+9

                     8x=16

                     x=16/8

                    x=2

substituir x em 2x +y = 7

                         2(2) + y=  7

                          4 + y = 7

                               y= 7 - 4

                             y = 3

S= {2,3}

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