Help! Will give medal and/or fan!

Please explain, don't just give the answer. I do want to learn :)

What change is needed to make this relation a function?
{(1, 2), (2, 5), (3, 8), (3, 9)}
Choose one answer.
A. Change the 8 to a 5.
B. Change one of the 3's to a number not yet used.
C. Change both 2's to 6's.
D. No changes are needed.

Question

Help! Will give medal and/or fan!

Please explain, don't just give the answer. I do want to learn :)

What change is needed to make this relation a function?
{(1, 2), (2, 5), (3, 8), (3, 9)}
Choose one answer.
	A. Change the 8 to a 5. 	
	B. Change one of the 3's to a number not yet used. 	
	C. Change both 2's to 6's. 	
	D. No changes are needed.

anonymous · Answer

Change one of the 3's into a number not used in the domain yet. (domain being the x value) x,y (y being the range). If you have more than one of the same x value, you dont have a function.

anonymous · Answer

understand it now??

anonymous · Answer

oh, I get it! Thank you so much!