Which relations are functions and which are not functions?

Column A Column B

1.

{ (2, 2), (4, 4), (6, 6),

(8, 8) }

2.

{ (0, 3), (3, 5), (5, 6),

(8, 4) }

3.

{ (1, 2), (3, 3), (4, 8),

(6, 3) }

4.

{ (3, 4), (5, 2), (5, 6),

(7, 3) }

A.

function

B.

not a function

A) A

B) A

C) A

D) B

Reason I know this is because if we look at the x number in all of these, if 2 are the same (like 2,6 and 2,4) then its a non function.

But if none of the x = the same value its a function.

Same goes for B

C

and now D, is a non function because out X's:

3

5

5

7

5 was repeated so it's a nonfunction.

Got it?

(I also just took this test XD)