# Chapter 1: Expressions, Equations, and Functions

**At Grade**Created by: CK-12

The study of expressions, equations, and functions is the basis of mathematics. Each mathematical subject requires knowledge of manipulating equations to solve for a variable. Careers such as automobile accident investigators, quality control engineers, and insurance originators use equations to determine the value of variables.

Functions are methods of explaining relationships and can be represented as a rule, a graph, a table, or in words. The amount of money in a savings account, how many miles run in a year, or the number of trout in a pond are all described using functions.

Throughout this chapter, you will learn how to choose the best variables to describe a situation, simplify an expression using the Order of Operations, describe functions in various ways, write equations, and solve problems using a systematic approach.

- 1.1.
## Variable Expressions

- 1.2.
## Order of Operations

- 1.3.
## Patterns and Expressions

- 1.4.
## Equations and Inequalities

- 1.5.
## Functions as Rules and Tables

- 1.6.
## Functions as Graphs

- 1.7.
## A Problem-Solving Plan

- 1.8.
## Problem-Solving Strategies: Make a Table; Look for a Pattern

- 1.9.
## Chapter 1 Review

- 1.10.
## Chapter 1 Test