Which set is a function?

A)
{(0,3), (3,0), (0,4), (4,0)}

B)
{(0,2), (2,0), (4,6), (6,4)}

C)
{(2,6), (3,6), (4,6), (2,0)}

D)
{(6,2), (2,0), (4,6), (6,4)}

Question

Which set is a function? 


 
 








  
A)
  {(0,3), (3,0), (0,4), (4,0)}   

 
  
B)
  {(0,2), (2,0), (4,6), (6,4)}   

 
  
C)
  {(2,6), (3,6), (4,6), (2,0)}   

 
  
D)
  {(6,2), (2,0), (4,6), (6,4)}

ybarrap · Answer

Notice that a function has only one y-value for every x value. So look at your options, are there any duplicates for the same x value? The one where there are no duplicates in the y-value for every x-value is your function.

ybarrap · Answer

For example, (0,4) and (0,6) is not a function because if I give you a 0 you can't choose whether to give me a 4 or a 6.

While (1,2) and (2,3) IS a functions because if I ask you for a 1 you give me a 2 and if I ask you for a 2 you give me a 3. The y-values are unique in functions.

ybarrap · Answer

I'll give you another example,

 {(6,2), (2,0), (4,6), (6,4)}   I give you a 6, what do you give me a 2 or a 4? Is this a function?