Respostas

2014-07-21T19:37:36-03:00
A) 
x=-6-y
-3x+2y=48

-3.(-6-y)+2y=48
18+3y+2y=48
5y=48-18
y=30/5
y=6

B)
x=4y
2x-7y=15

2.4y-7y=15
8y-7y=15
y=15


1 4 1
2014-07-21T19:41:28-03:00
X+y=-6 (x3)
-3x+2y=48

3x+3y=-18
-3x+2y=48

3y+2y=48-18
5y=30
y=6

x+6=-6
x=-12



x-4y=0 (-2)
2x-7y=15

-2x+8y=0
2x-7y=15

8y-7y=15
y=15

x=4.15
x=60