Respostas

2013-08-19T22:52:56-03:00
A) x=3 e y=2
3-(2)+2(3) - 4(2)=
3-2 + 6 - 8 =-1
b) vc repetiu 
c) x-y+2x-4y
4-4+2.(4) - 4(4)=
4-4+8 - 16= -8





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