In the previous section, we talked about lines briefly, in the context of constructing a line between two points. We calculated the distance between any two points, learned how to find a midpoint, and defined the concept of the gradient, or "steepness," of the line connecting these points.

With every concept we discussed, we went from two points to a line between them. In this section, our goal will be to define lines outside of this framework, so we can go from finding the equation for a line to choosing two points anywhere on it.

In this section, we will learn several different ways to write the equation of a line.