So we took its y minus the other point's y. So to be consistent, we're going to have to take this point's x minus this point's x. So this point's x-coordinate is b. So it's going to be b minus a. And just like that, if you knew the equation of this line or if you had the coordinates of these two points, you would just plug them in right here and you would get your slope. That straightforward. And that comes straight out of your Algebra 1 class.