8.4 Introduction to functions
Introduction to functions
Bring on more grid papers! In this chapter, we’re going to study functions. Functions are notations that tell us what the value of y is for every value of x. By carrying out the vertical line test, we are able to find out the relationships of ordered pairs.
Basic concepts:
 Solving linear equations by graphing
 Relationship between two variables
 Understand relations between x and yintercepts
 Domain and range of a function
Related concepts:
 Characteristics of quadratic functions
 Basic radical functions
Lessons
Notes:
Relations: Sets of ordered pairs ( x , y )
Function: For every value of x, there is a value of y. It will need to pass the vertical line test.
OneToOne Function: For every one value of x, there is only one value of y, and vice versa. It will need to pass both vertical and horizontal line test.
Vertical line Test: A vertical line that intersects the graph of the equation only once when moves from across on the xaxis.

1.
Are the following sets of ordered pairs functions?

3.
Using the table of values to answer the questions below: