This document discusses linear equations in two variables. It defines a linear equation as an equation that can be written in the standard form of ax + by = c, where a, b, and c are real numbers and a and b are not both equal to 0. The document provides examples of determining if equations are linear and writing them in standard form. It also discusses how to determine if an ordered pair is a solution to a linear equation and how to graph linear equations using tables of values, x- and y-intercepts, and slope-intercept form.