Here's another one of my favorite apps. Its gotten a lot of mileage and originally started out on a TI-81. It asks for X1, Y1, X2, Y2 which is typically in a text book as (X1, Y1), (X2, Y2). Plop the 2 coordinates in and it tells you the slope (M), distance between the two points, and the X and Y intercepts (if available).
