Respostas

2014-05-13T16:03:18-03:00
X+y=5
x-y=1
2x=6
x=6/2 = 3

x+y=5
3+y=5
y=5-3=2

3x+3y = 3(3) + 3 (2) = 9 + 6 = 15
2014-05-13T16:08:50-03:00
x+y = 5
x - y = 1

x + y + 5 + x - y + 1 =
2x = 6
 x = 6 / 2
 x = 3

3 - y = 1
-y = -3 + 1
 y = 2

valores de x = 3
vlores de y = 2

3x + 3y =
3.(3) + 3.( 2 )
  9  +  6 = 15

portanto 3x + 3y = 15