Answer
$C(x)=0.80x+40$
Work Step by Step
We need to express the cost as a function of number of miles driven.
Given that, a moving truck charges $\$40$ per day plus mileage charge of $\$ 0.80$ per mile.
Let $x$ be the number of miles driven.
Let $\$40$ be the fixed charge, then $\$0.80$ represents the mileage charge.
Hence the cost $C$ to rent the truck is $C(x)=0.80x+40$.
