The cost $C,$ in dollars, of renting a moving truck for a day is given by the function $C(x)=0\mathrm{.}20x+45,$ where $x$ is the number of miles driven.

$($a$)$ What is the cost if a person drives $x=80$ miles?

$($b$)$ If the cost of renting the moving truck is $$60,$ how many miles did the person drive?

$($c$)$ Suppose that a person wants the cost to be no more than $$120.$ What is the maximum number of miles the person can drive?

$($d$)$ What is the implied domain of $C?$

$($a$)$ The cost is $

$($Type an integer or a decimal.$)$

$($b$)$ The person drove miles.

$($Type an integer or a decimal.$)$

$($c$)$ The person can drive miles maximum.

$($Type an integer or a decimal.$)$

$($d$)$ The implied domain of $C$ is

$($Type your answer in interval notation.$)$