The table below shows the fourth powers of different numbers
number x : 1 1 2 2
fourth power of the number y : 1 1 16 16
part a: does the table represent y as a function of x? justify your answer
part b: the total cost f(x), in dollars, for renting a truck for x hours is shown below:
f(x) = 17x + 50
what is the value of f(30) and what does f(30) represent?

Part A
When x=1, x⁴ = 1⁴ = 1
 Because y = 1, x⁴ = y.
When x=2, x⁴ = 2⁴ = 16
 Because y = 16, x⁴ = y

y = x⁴ according to the given table.
For each given x, there is only one value of y, so it is a function.

The table represents a function of x.

Part B
f(x) = 17x + 50
where
x = hours to rent a truck
f(x) = cost in dollars

When x = 30 hours, f(30) = 17*30 + 50 = $560

f(30) represents the cost in dollars to rent a truck for  30 hours.
The value of f(30) is $560.