Question

Which relation is also a function?
A. {(1.5, 4) (2, 4) (2.5, 5) (3, 5) (2, 6)}
B. {(-1, 3) (-1, 2) (-1, 4) (-1, 5) (-1, 6)} C. {(-2, 0) (1, 3) (-2, 1) (1, -3) (-2, 6)}
D. {(1, 7) (2, 3) (4, 10) (6, 12) (8, 15)}

Answer 1

the one where the first numbers to not repeat

Answer 2

huh?

Answer 3

not A, the 2 repeats
not B, the -1 repeats
not C, the -2 repeats

only in D are the first numbers all different

Answer 4

all the first numbers in the ordered pairs have to be different to make it a function
if any of the first numbers repeats, it is not a function

Answer 5

is it clear what i meant?

Answer 6

yea kinda

Answer 7

look at the first numbers in the ordered pair.
if you see a repeat, then not a function
in the first set of ordered pairs there is both \((2,4)\) and \((2,6)\)
since the first number in both pairs is 2, not a function