Calculate the Straight Line Graph
If you know two points, and want to know the "y=mx+b" formula (see Equation of a Straight Line), here's the tool for you.
Just enter the two points below, the calculation is done live.
algebra/images/calc-straight-line.js
When the two points have the same x-coordinate, like (3, 5) and (3, 8), the line is vertical (straight up and down) ... the equation of the line is x = [value] (for example, x=3), not y = mx+b ... and the slope is undefined.