Which one of the following sets of ordered pairs does NOT show a constant rate of
change?
1,5) (3,15) (4.5, 22.5) (9, 45)
(2,6) (3,9) (6,18) (8,24)
(1,4.5) (2,9) (4,18) (5,22.5)
(2,8) (3,15) (8,20) (9,36)