How do you determine if a mapping, table, or set of ordered pairs represents a function?

Question

A-all x values are different

B-some x values repeat

C-some y values repeat

D-all y values are different

I really have no clue what it is.

Answer 1

You can only have one value of y for each value of x
if x values were to repeat, they would have to have the same y value, which would be kind of unnecessary and meaningless.

Answer 2

so would it be d?

Answer 3

No, a parabola, for example y = x^2 is a function. There is one and only one value of y for every x
y s the same , +1 , for x = -1 and for x = +1

Answer 4

I think the x values should be different :)

Answer 5

Thank you sooo much!

Answer 6

you cannot have the same x value twice. For example,
(2,3) and (2,4)
How can f(2) be 4 , if f(2) = 3?

Answer 7

if you had x = 0, y = 5
and also
x = 0, y = 7
that would NOT be a function