MINI LESSON

Defining Functions

A function is a relation in which each input has exactly one output.

You can test a relation by checking ordered pairs, tables, mappings, and graphs. If one input is paired with two different outputs, the relation is not a function.

On graphs, use the vertical line test: if any vertical line hits the graph more than once, the graph does not represent a function.

Question 1

Three relations are shown below. Which relations represent a function?

Question 2

Which of the graphs represent(s) a function?

Question 3

Given the relation R = {(-1,1),(0,3),(-2,-4),(x,5)}, which value of x will make the relation a function?

Question 4

The table below represents a relation. What value of x would make the relation a function?