1. Which relation is not a function? Explain.
1) {(1,5),(2,6),(3,6),(4,7)} 2) {(4.7).(2,1),(-3,6),(3,4)}
3) ((-1,6),(1,3),(2,5),(1,7)} 4){(-1,2),(0,5),(5,0),(2,-1)}
7 Which function is not one-to-one? Fynlain