Determine which relation is a function.

A.
{(–4, 3), (–2, 3), (–1, 2), (2, 5), (3, 2)}

B.
{(–4, 1), (–2, 3), (–2, 1), (–1, 5), (3, 2)}

C.
{(–4, 1), (–2, 3), (–1, 2), (3, 5), (3, 2)}

D.
{(–4, 1), (–2, 3), (–1, 1), (–1, 5), (3, 2)}

Question

Determine which relation is a function.	
 
 A.
{(–4, 3), (–2, 3), (–1, 2), (2, 5), (3, 2)}
 
 B.
{(–4, 1), (–2, 3), (–2, 1), (–1, 5), (3, 2)}
 
 C.
{(–4, 1), (–2, 3), (–1, 2), (3, 5), (3, 2)}
 
 D.
{(–4, 1), (–2, 3), (–1, 1), (–1, 5), (3, 2)}

mathstudent55 · Answer

In a function, each value of the x-coordinates can only be used once.
If you see the same x-coordinate used more than once, it is not a function.