We have already seen some **equations** when working with **formulae**.

An equation is a type of **relationship**, where we compare one **expression** with another expression. What are the other kinds of relationship you have met (in mathematics!)

When we talk about **solving an equation**, we mean finding the value of the **variable** (i.e. the letter) in the equation. If it has more than one **variable** we sometimes talk about e.g. **solving for y** to make clear which variable we are interested in.

Our study of equations and inequalities will be broken into the following topics:

2.) Constructing equations from word problems (and then solving them);

3.) Linear inequalities;

4.) Simultaneous equations (sometimes called systems of equations);