The table shows the outputs y for different inputs x:
input
(x) 3 7 11 15
output
(y) 4 6 8 10
part a: do the data in this table represent a function? justify your answer. (3 points)
part b: compare the data in the table with the relation f(x) = 5x – 21. which relation has a greater value when x = 11? (2 points)
part c: using the relation in part b, what is the value of x if f(x) = 99? (5 points)

Part A: Yes, the data represent a function. The definition of a function is a relation in which no value of x will have two different values of y.
(Every time you plug in 3 as x, you will always get 4 as y; it's ok if you plug in 3 and 5 as x and get the same y, you just can't get two different y's for one x; sorry, it is pretty confusing). None of the numbers in the table repeat, so we can safely say that the relation is a function.

Part B: All we have to do is plug in 11 for x in the function given to find the

In the table, y = 8 when x = 11, but in the function given, y = 34 when x = 11, so the function given is greater.

Part C: To find the answer to C, just plug in 99 for f(x), as it tells you to do: