Respostas

2014-05-22T20:00:02-03:00
X+y=3
x-y=9
2x=12
x=12/2
x=6

2x-2y=12
x+2y=11
3x=23
x=23/3
x= 8  aproximadamente

x+y=7
x+2y=11
2x+3y=18

-3x-2y=12
x-5y=3
-2x-7y=15

-3x-2y=-1
2x25y=12
5x+3y=11