Respostas

2013-12-16T17:15:06-02:00
Método da adição:

x-y=70
x+y=50

2x=120
x=120/2
x=60

x+y=50
60+y=50
y=50-60
y=-10
1 5 1
2013-12-16T17:15:43-02:00
X-y=70
x+y=50


2x=120
x=120/2
x=60

x+y=50
60+y=50
y=50-60
y=-10