Well, the first part should be pretty easy to make urself, if ur just askin for the slope between 2 points.
: Disp "Y1?"
: Input A
: Disp "Y2?'
: Input B
: Disp "X1?"
: Input C
: Disp "X2?"
: Input D
yea, u can figure it out from there. I'm not sure, i know i used to have a program for Arithmetic Sequences.....
[Edit] Heh, the lines made smilies, LOL! [/edit]