Basic Algebra question

[TMW2010]

Yes, I've edited the post because I misread what Cook was asking :p

The slope is rise (y2-y1) over run (x2-x1) with the line going from Left(x1,y1) to Right(x2,y2)... If you have a point at (0,0) and a point at (3,3) the slope would be (3-0)/(3-0) or 1/1 or 1 in simplified format.

If you had a point at (-1,1) and a point at (-4,2) the slope would be (1-2)/(-1-(-4)) or -1/(-1+4) which equals -1/3.

Even though I wrote the (-1,1) first in that sentence, (-4,2) is actually the left-most point of the two points given on the line, and that would be your (x1,y1) point. I was incorrect in stating this, it doesn't matter which you choose as your first point.