This applet allows students to interact with a line, its slope and the y-intercept. They can explore how the line changes and the slope changes when points are moved, or the slope is altered.
When the slope changes, what does the line do? When the y-intercept changes, what does the line do? When the points are moved, what does the slope do? What does the graph look like when the slope is positive? Negative? 0? Undefined?