Now you should go the applet below and practice moving the sliders and finding points of intersection for lines you create.

When you have the graph set on slope-intercept form, y = mx + b, you can also directly enter the slope and y-intercept by pressing SET m or SET b. When you press either box, a small text box will come up for you to enter the slope m or the intercept b. You then press OKAY for the graph to move.

When you have the graph set on general form, ax + by = c, you can also directly enter a, b, and c into the graph by using SET a, SET b, or SET c.