Part A. Notice that

,

,

, and

. If we let

represent the number that is being cubed and

the result of that operation, we can create the function

whose domain and range are the set of all real numbers.
We can conclude that the table represent the cube function

.
Part B. To find the value of

, we just need to evaluate the total cost function

at

; in other word, we are going to replace

with 6 in the function:




Since

represent the number of days you are going to rent a car, it

represent the cost of renting a car for 6 days.
We can conclude that the value of

is $180, and it represent the cost of renting a car for 6 days.