You divide your graph into 3 parts also.
One for the case when
Needless to say, this equation is linear.
To graph, select any 2 numbers that satisfy
Substitute the values into the equation to get the corresponding
Finally, connect the points.
For simplicity, let's choose
Since the equation is only true for
the point hollow.
Graph this by drawing a point at
Again, this equation is linear.
Choose any two values of
For demonstration, let's choose
Connect the points
Extend this up to the point where
Similar to the case when
Extend your other end indefinitely and you have your graph.