Respostas

  • Usuário do Brainly
2014-06-12T00:07:41-03:00
A)  x+y =7
         x= 7-y
x - y= 3
7 - y - y =3
-2y =-4
y=2

x=7- 2=5
(5,2)

b) x+2 =3
   x=1
y=3
(1,3)

c) x=1
4+y=2y-x
4 +y = 2y - 1
y=5
(1,5)