# Chapter 7: Algebraic equations (Part 1)

## 7.1 Introduction

A musical note one octave lower than another has exactly half the frequency of the higher note. Here is an example showing a high note \(A\), and an \(A\) note one octave lower.

In this chapter, you will learn to find numbers that make certain statements true. A statement about an unknown number is called an equation. When we work to find out which number will make the equation true, we say we solve the equation. The number that makes the equation true is called the solution of the equation. Sometimes there are many solutions and sometimes there is only one.