A

**quadratic expression** is one where the largest power for the

variable is 2. Some examples of quadratic

expression are shown below.

A

**quadratic equation** is an

equation where the largest power for the

variable is 2. Remember that an

equation has an equal sign in it. Some examples of quadratic equations are:

Quadratic equations can be solved in order to find the

** roots** of the equation. Roots are also called

**zeros** or

**x–intercepts** if the

graph crosses the x–axis. The roots of a

quadratic equation simply tell what values of x will make the

equation true.

A

**quadratic function** is a

function where the largest power for the

variable is 2. A

function usually takes the form of y = or f(x) =.

So what are the key differences between an

*expression*, an

*equation*, and a

* function*?

- A quadratic
*expression* is usually just something that can be simplified or factored. You cannot solve an expression for a variable. You can only manipulate the terms you are given. - A quadratic
* equation* is given to you so that you can solve it for the variable. - A quadratic
*function* is given to you so that you can graph it.