The table shows the outputs, y, for different inputs, x:

input (x) 2 5 9 12
output (y) 20 15 12 8

part a: do the data in this table represent a function? justify your answer.

part b: compare the data in the table with the relation f(x) = 5x + 14. which relation has a greater value when x = 9?

part c: using the relation in part b, what is the value of x if f(x) = 64?