Which set of ordered pairs represents a function? {(0,1), (1,3), (1,5) (2,8)}, {(0,0), (1,2), (2,6), (2,8)}, {(0,0), (0,2), (2,0), (2,4)}, {(0,2), (1,4), (2,6), (3,6)}

The last set.

Step-by-step explanation:

The first 3 sets  contain  'one-to-many' relations , for example (1, 3) and (1, 5) in set 1 and (0, 0) and (0, 2) in set  3 , so they are not functions.

The last set does not have any of these and is a function.

if you was gonna solve for a, a is a   < -12