Respostas

  • Usuário do Brainly
2014-01-23T17:24:05-02:00
2x+y=140
x+3y=170 = x=170-3y
           
2x+y=140
2(170-3x) +y=140
340-6y+y=140
-6y+y=140-340
-5y=-200 (-1)
y=200/5
y=40
 logo temos:   x=170-3y
x=170-3(40)
x=170-120
x=50