Question

o senhor tem coelhos e galinhas no total de20 cabeças 58pes . determine o número de coelhos e de galinhas

Answer 1

  x+y=20(-2) ______________________________________ x+y=20
4x+2y=58                                                                       9+y=20
                                                                                      y=20-9
-2x-2y=-40                                                                       y=11
4x+2y=58
excluir o -2y e 9y, pois são opostos
2x=18
x=9