Which of the following relations is a function?
A. {(-4, 3), (-4, 2), (1, 9), (6, 7)}
B. {(-4, 3), (-2, 0), (2, 7), (3, 9)}
C. {(2, 1), (4, 2), (2, 3), (8, 4)}
D. {(0, 0), (0, 1), (2, 3), (4, 5)}

Question

Which of the following relations is a function?
	A.	{(-4, 3), (-4, 2), (1, 9), (6, 7)}
	B.	{(-4, 3), (-2, 0), (2, 7), (3, 9)}
	C.	{(2, 1), (4, 2), (2, 3), (8, 4)}
	D.	{(0, 0), (0, 1), (2, 3), (4, 5)}

anonymous · Answer

A relation is any group of ordered pairs...  But, a FUNCTION is a group of ordered pairs where any x value HAS ONLY ONE y output!

anonymous · Answer

So, look at A.  notice that -4 has TWO possible outputs...   (If I asked you what is the y-value of -4, you could not give me one answer... )  Therefore, A is not a function...

anonymous · Answer

Then, look at C:  Notice that 2 has more than one unique output... Therefore, it is not a function...

anonymous · Answer

So, is it B or D?

anonymous · Answer

d

anonymous · Answer

Nope... the answer is B...
In D ---  the value 0 has TWO outputs  (0 and 1)...  
But, in B --- every x value has exactly ONE output...

anonymous · Answer

Make sense?

anonymous · Answer

nooo .

mertsj · Answer

Perhaps this form of the definition will help you:  A function is a set of ordered pairs in which no two ordered pairs have the same first number.