The slope of a line tells how steep it is. A line with a positive slope runs uphill, while a line with a negative slope runs downhill. If you graph a two-variable equation and form a straight line, this is a linear equation. Linear inequalities are represented with signs other than the equal sign (=), such as less than (<) or greater than (>).

There may be several ways to represent the same algebraic expression. Any letter can represent an "unknown."

Terms to know in this unit include: