1.1 Introduction

Do you remember what linear functions are from previous math classes? Linear functions describe a linear relationship between two variables. Suppose you are at a gas station and you can purchase gasoline for $2.00 per gallon. If you purchase only 1 gallon, you will pay $2.00; if you purchase 2 gallons, $4.00; and if you purchase 10 gallons, $20.00. If you purchase x gallons of gasoline, then you will pay x times $2.00. When we graph this relationship, we expect the line that connects the cost of gasoline and the number of gallons purchased to be straight. This is an example of a linear function.

In this topic, we are going to learn how to form, graph, and transform linear functions.