Respostas

2013-12-18T16:41:44-02:00
Temos: x+y=28 (1) e x-y=16 (2) então x=16+y (3)

Substituindo(3) e (1) :
(16+y) + y = 28
16 + 2y = 28
y= 28-16/2
y = 12/2
y = 6


x + y = 28
x + 6 = 28
x = 28-6
x = 22
1 5 1
2013-12-18T16:51:49-02:00
X+y=28
x-y=16

2x=44
x=44/2
x=22

x+y=28
22+y=28
y=28-22
y=6