where and are the coordinates of the given points.
Of course, this will only provide an equation of the desired line. There are (many) more than one representations of any given line, so it is impossible to write the equation of a line.
Once you have substituted your given coordinate values and done the indicated arithmetic, you can either leave it in that state, put it into slope-intercept form (), or put it into standard form () as you (or, perhaps more to the point, as your instructor or textbook) desire(s).
John
My calculator said it, I believe it, that settles it
