Question

~PLEASE HELP ASAP OFFERING 15 POINTS~

The daily expenses for each of a transportation service company’s trucks is given by the function d(x) = 15 + 0.5x, where d(x) is the daily expense per truck (in dollars) and x is the daily mileage.

The input for the function includes

A) All fractions

B) All Integers

C) All real numbers

D) All positive real numbers

Answer 1

The function only makes sense for
D) All positive real numbers

_____
It also makes sense for x=0, which would make the domain "all non-negative real numbers." However, that is not a choice.

As shown, the function is defined for all real numbers, which includes all fractions and all integers. However, in the real world, you won't be driving the truck a negative number of miles and you won't be charged less than $15 per day. So, in the real world, the practical domain of the function is as described above.