Respostas

2013-11-05T19:13:55-02:00
9x - 13y = 
9.(-8) -13.(-5) = 
-72 + 65 = - 7 

2 3 2
2013-11-05T20:04:04-02:00
9x- 13y
9*(-8) - 13*(-5)=-7
1 3 1