1 Which relation is not a function?

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)}

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)