Graphs of equations: Is the point IN or OUT?
An equation tells you a set of points by giving you a rule for telling if a point is in or out. If the coordinates of the point satisfy the equation then the point is in; if the coordinates of the point don't satisfy the equation then the point is out. Type in your own equation and move the point around to see which points are in or out. The point will be blue when it's out of the set and red when its in the set. Try to figure out what shape the graph is from the red points left behind.