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?

Respuesta :

A Yes  as the x values are all different

B f(x) = 5x + 14

when x = 2 , f(x) = 5(2) + 14 = 24
 x = 5,  f(x) = 39, 
Each value of f(x) is greater than corresponding ones in the function in A.
when x = 9  f(x) = 59  which is greater than for first function ( =12)

First function is a decreasing  while f(x) is increasing

C f(x) = 64 = 5x + 14

5x  = 64 - 14 = 50

x = 10