// A bit long perhaps, but hey you get everything you need to know and more

NAME:POINTSLP

:Lbl 1
:ClrHome
:Disp "AX-BY=C"
:Disp ""
:Disp "Enter Slope"
:Disp "A/B"
:Disp "A="
:Input A
:Disp "B="
:Input B
:ClrHome
:Disp "(X,Y)"
:Disp ""
:Disp "ENTER POINT"
:Disp "X="
:Input X
:Disp "Y="
:Input Y
:A(X)-B(Y)->C    * // -> is the STO key
:ClrHome
:Disp "C="
:Disp C
:If B=0
:Goto L
:If A=0
:Goto N
:C/A->D
:C/-(B)->E       * // Keep in mind the first '-' is the negative, not minus sign
:Disp "X INT="
:Disp D
:Disp "Y INT="
:Disp E
:"(A/B)X-C/B"->Y1   * // To get Y1, goto 2nd Y-Vars and hit ENTER
:Pause
:Goto 3
:Lbl L
:If A=0
:Goto P
:ClrHome
:Disp "NO Y INT"
:Disp ""
:Disp "X INT="
:Disp X
:Disp ""
:Disp "NO SLOPE"
:Pause
:Goto 4
:Lbl N
:ClrHome
:Disp "NO X INT"
:Disp ""
:Disp "Y INT="
:Disp Y
:Pause
:"C/-B"->Y1     * // First '-' sign is negative again
:Goto 3
:Lbl P
:ClrHome
:Disp "NO SOLUTION"
:Pause
:Goto 4
:Lbl 3
:Disp "GRAPH (1=YES)"
:Input Z
:If Z=1
:Goto 2
:Lbl 4
:ClrHome
:Disp "ANOTHER (1=YES)"
:Input Z
:If Z=1
:Goto 1
:End
:Lbl 2
:DispGraph
:Pause
:Goto 4

// Written by defc0n (defc0n@netscape.net)