#### Answer

$C(x)=0.28x+44$

#### Work Step by Step

In a cost function of the form $C(x)=mx+b$,
m represents the marginal cost and
b represents the fixed cost.
Here,
b= $\$ 44$ (fixed cost) and
m= $\$ 0.28$ (the cost per mile).
Let
$x=$ the number of miles;
$C(x)=$ the cost of renting for $x$ miles.
$C(x)=0.28x+44$