Use the domain and range of each of the following relations to determine which is a function.

a. [tex]$\{(3,-3),(9,-6),(0,-9)\}$[/tex]

b. [tex]$\{(3,-3),(9,-6),(3,-9)\}$[/tex]

c. [tex]$\{(3,-3),(9,-6),(9,2),(0,-9)\}$[/tex]

d. [tex]$\{3,9,0,-4\}$[/tex]

Please select the best answer from the choices provided:

A. a

B. b

C. c

D. d



Answer :

To determine which of the given relations is a function, we need to understand the definition of a function. A relation is a function if each input (or domain) corresponds to exactly one output (or range).

Let's analyze each relation:

a. [tex]\(\{(3, -3), (9, -6), (0, -9)\}\)[/tex]

For this relation, we can list the pairs:

- Input 3 maps to output -3.
- Input 9 maps to output -6.
- Input 0 maps to output -9.

Each input has a unique output, so this relation is a function.

b. [tex]\(\{(3, -3), (9, -6), (3, -9)\}\)[/tex]

For this relation:

- Input 3 maps to output -3.
- Input 9 maps to output -6.
- Input 3 also maps to output -9.

Here, the input 3 maps to two different outputs (-3 and -9), so this relation is not a function.

c. [tex]\(\{(3, -3), (9, -6), (9, 2), (0, -9)\}\)[/tex]

For this relation:

- Input 3 maps to output -3.
- Input 9 maps to output -6.
- Input 9 also maps to output 2.
- Input 0 maps to output -9.

Here, the input 9 maps to two different outputs (-6 and 2), so this relation is not a function.

d. [tex]\(\{3, 9, 0, -4\}\)[/tex]

For this relation, there are no pairs of inputs and outputs, just a list of numbers. This does not fit the definition of a function because it lacks the structure of pairs of values representing the domain and range.

Hence, upon examining each relation, we conclude that the given relation that is a function is:

A

So, the best answer is A.