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

Question

Input (x)
13
5
7
Output (y)
8
6
5
4

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) = 4x + 8. Which relation has a greater value when x = 3? (2 points)

Part C: Using the relation in Part B, what is the value of x if f(x) = 76? (5 points)

Answer 1

There is one and only one value of y for each value of x, so yes

4(13) + 8 = 60
4(5) + 8 = 28
4(7)+8 = 36
or
4(3)+8 = 20

4 x + 8 = 76
4 x = 68
x = 17