Respostas

2014-08-21T23:03:55-03:00
Olá...

(a)x = y + 2 
(b)x - 2y = 18

(a)-->(b)

y+2 - 2y = 18
-y = 16
y = -16

(a) x = y + 2 
     x =-16 + 2
     x = -14

=)