Question

PLEASE HELP!!! WILL GIVE FAN AND MEDAL!!

Determine which relation is a function.

A.
{(–3, 2), (–2, 3), (–1, 1), (0, 4), (0, 1)}

B.
{(–3, 3), (–2, 3), (–1, 1), (0, 4), (0, 1)}

C.
{(–3, 2), (–1, 3), (–1, 2), (0, 4), (1, 1)}

D.
{(–3, 2), (–2, 3), (–1, 2), (0, 4), (1, 1)}

Answer 1

My guess was D but I'm not 100% sure.

Answer 2

@vheah can u help?

Answer 3

What I usually do is graph the points separately for each choice and do a vertical line test. Whichever one passes the vertical line test is a function. Do you know what a vertical line test is?

Answer 4

yes, I know that 2 points can't be on the same vertical line.

Answer 5

also, I know A is wrong.

Answer 6

Another thing you could do is you make a table of x and y
Example (using choice B) :
{(–3, 3), (–2, 3), (–1, 1), (0, 4), (0, 1)}

x: -3, -2 -1 0 0
y: 3 3 1 4 1

Each x should be paired with one y, however the numbers in x should not repeat. Since 0 repeated in one of the given points, then choice B is not a function.

Answer 7

Let's try C:
{(–3, 2), (–1, 3), (–1, 2), (0, 4), (1, 1)}

x: -3 -1 -1 0 1
y: 2 3 2 4 1

Still not a function, since -1 repeats in x

Answer 8

And D:
{(–3, 2), (–2, 3), (–1, 2), (0, 4), (1, 1)}

x: -3 -2 -1 0 1
y: 2 3 2 4 1

D does not have numbers repeating on x, therefore D is a function. So you are right. Do not worry about the numbers repeating on the y. What makes a group of points not a function is when a coordinate x repeats. I hope that made sense.