Two point [math]A[/math] and [math]B[/math] can be moved.  The resulting slope of the line through those two points is shown as a rise over run triangle as well as in equation form.  The equation of the line through the two points is also shown.

For this applet move the two points about the plane.[br][br]When is the slope negative?[br][br]How does the last term in the [math]y=mx+b[/math] equation relate to the location where the line crosses  the y axis?[br][br]When is the slope zero?[br][br]When is the slope undefined?