Which relation is not a function?
a. {(0,9), (2,3), (3,2), (4,1)}
b. {(3,2), (4,1), (0,9), (3,3)}
c. {(0,3), (2,3), (3,3), (4,3)}
d. {(0,3), (3,2), (2,4), (4,6)}

Question

Which relation is not a function?
a. {(0,9), (2,3), (3,2), (4,1)}
b. {(3,2), (4,1), (0,9), (3,3)} 
c. {(0,3), (2,3), (3,3), (4,3)}
d. {(0,3), (3,2), (2,4), (4,6)}

anonymous · Answer

This is a tricky question that Math teachers give to make you think about the definition of a function.  Every function assigns one value to y for every value of x.  So look for the entry that doubles up on y values for one value of x.