Straight line graph
Did you notice that when we made the graph of 
Because all of the coordinates are on the same straight line, we only need two coordinates to draw the line.
We could have just plotted the points (0, 1) and (3, 7), for example.
Drawing a line through these points connects all of the points on the line where
We can see that the line passes through all of the coordinates given in the table below
 | -1 | 0 | 1 | 2 | 3 | 4 |
 | -1 | 1 | 3 | 5 | 7 | 9 |
