Which set of ordered pairs is not a function?
1) {(3,1),(2,1),(1,2), (3, 2)} 2) {(4,1),(5,1). (6, 1), (7, 1)}
3) {(1,2), (3,4),(4,5),(5,6)} 4) {(0,0),(1, 1), (2, 2), (3, 3)}
You can have the same y value multiple times in a function, but you cannot have repeating x values. In set 1, there are two x values that are the same (3,2) and (3,1), so it is not a function.
