Someone
which relation is a function?

a.
x −2 −2 0 1 8
y 3 6 0 0 9

b.
x 3 5 7 14 14
y −9 5 −9 1 2

c.
x −3 4 5 9 12
y 1 −2 −2 0 7

d.
x −7 −5 6 8 8
y −3 8 1 1 −9

A function has 1 input gives only one output
you cannot have
input 2 and get 4
then later
input 2 and get 6, that is not a function

basically x never repeats with a different y so

A. the -2 repeats with the 3 and 6
B. the 14 repeats with 1 and 2
C. no repeats
D. 8 repeats with 1 and -9

answer is C because the rest have some repeats