PreCalculus

11.1. Linear functions

A linear function can be represented graphically as a straight line on the Cartesian plane by writing it in the form:

y = ax + b

This equation defines the set of ordered pairs {x, y} that may be used to draw a graph.

General equation of a line

A linear function may be written in the form of the general equation for a line in two dimensions:

Ax + By + C = 0

Either A or B may be zero, but not both. For example, consider the linear function:

y = 2x - 2

This can be rewritten in the general form of the equation of a line:

2x - y - 2 = 0