Let x = 0

x + 2y = 6
0 + 2y = 6
    2y = 6
     y = 3

So one ordered pair is (x,y) = (0,3)


Let y = 0

  x + 2y = 6
x + 2(0) = 6
       x = 6

So another ordered pair is (x,y) = (6,0)

Let x = 2

x + 2y = 6
2 + 2y = 6
    2y = 4
     y = 2

So a third ordered pair is (x,y) = (2,2)

Plot the points corresponding to those three ordered pairs:

   

Edwin