Understand that a function is a rule that assigns to each input exactly one output. The graph of a function is the set of ordered pairs consisting of an input and the corresponding output.

How is a Function Defined?

You can't go through algebra without learning about functions. This tutorial shows you the definition of a function and gives you an example of a function. Take a look!
How Do You Figure Out If a Relation is a Function?

How do you figure out if a relation is a function? You could set up the relation as a table of ordered pairs. Then, test to see if each element in the domain is matched with exactly one element in the range. If so, you have a function! Watch this tutorial to see how you can determine if a relation is a function.
How Do You Use the Vertical Line Test to Figure Out if a Graph is a Function?

Trying to figure out if an equation is a function? Graph it and perform the vertical line test. If it passes, then it's a function! Get some practice by watching this tutorial!
What's a Function?

You can't go through algebra without learning about functions. This tutorial shows you a great approach to thinking about functions! Learn the definition of a function and see the different ways functions can be represented. Take a look!
What's the Vertical Line Test?

Even graphs need to worry about tests! Using the vertical line test, you can figure out if a graph is a function or not. Watch this tutorial and learn about the vertical line test. Then, put your graphs to the test!