Respostas

2014-06-21T21:40:39-03:00


x = 4 - y

2(4 - y) - y = 15
8 - 2y - y = 15
-3y = 15 - 8
-y = 7/3 (-1)
y = -7/3

x - 7/3 = 4
x = 4 + 7/3
x = 19/3
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2014-06-21T21:41:51-03:00
2x-y=15
x+y=4⇒x=4-y⇒x=4-(-7)⇒x=11

2(4-y)+y=15
8-2y+y=15
-y=7
y=-7

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