Question

The table shows the outputs y for different inputs x:

Input
(x)
5 6 7 8


Output
(y)
2 5 8 11


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) = 2x + 13. Which relation has a greater value when x = 7?

Part C: Using the relation in Part B, what is the value of x if f(x) = 75?

Answer 1

Part A: the data represent a function because for each value of x, there is a unique value of y.

Part B: from the table, when x = 7, y = 8. from the function f(x) = 2x + 13, f(7) = 2(7) + 13 = 14 + 13 = 27.
Hence f(x) = 2x + 13 has a greater value when x = 7.

Part c: f(x) = 2x + 13 = 75
2x = 75 - 13 = 62
x = 62/2 = 31