Which of the following sets of ordered pairs is not a direct variation?
a. (0, 0); (-2, 4); (3, -6)
b.(1, 1); (-2, -2); (3, 3)
c.(10, 2); (15, 3); (20, 4)
d.(0, 0); (1, 3); (2, 4)

The answer would be a 

1. 0.3 •4 is the same as 4 groups of 0.32. 7•0.8 is the same as 7 groups of 0.83. it increases by 0.5 every time, so 0.5x4 it increases by 0.9 every time, so 0.9x5. 0.9•12=10.86. 0.47•5=2.35i can finish the next ones in a separate post