Which of the following sets represents a function?

{(3, 5), (-1, 7), (3, 9)}
{(1, 2), (3, 2), (5, 7)}
{(1, 2), (1, 4), (1, 6)}

Question

Which of the following sets represents a function?

{(3, 5), (-1, 7), (3, 9)}
{(1, 2), (3, 2), (5, 7)}
{(1, 2), (1, 4), (1, 6)}

jack1 · Answer

all

jack1 · Answer

what type of function specifically are you looking for?

compassionate · Answer

Wrong, Jack. It cannot b C as you can't have the same x value twice and get a different y value.

compassionate · Answer

If you look at A you see we put in 3 as the x value and got a different y value.

jack1 · Answer

its a horizontal line, can be a function y = x +c

anonymous · Answer

so is it a?

compassionate · Answer

It can't be A as we use the same x-value and get different y-values 
It can't be C as 1 gives us differnet y values.

anonymous · Answer

oh ok i get it

compassionate · Answer

Yea, it's like if I had: y = 2 + x. 

If I put x = 1 
y = 2 + 1. y = 3. It is impossible for me to get any other y value by inserting 1 other than 3. 

Basically, if the x value happens more than once and you get a different y-value, it's not a function.