#### Answer

$C(x)=180x+2000$

#### Work Step by Step

In a linear cost function, of the form
$C(x)=mx+b$,
the $m$ represents the marginal cost and
$b$ represents the fixed cost (zero units produced).
The graph of C(x) passes through the points
$(36, 8480)$ and $(0,2000).$
Slope: $m=\displaystyle \frac{8480-2000}{36-0}=\frac{6480}{36}=180$.
Slope-intercept equation:
(b= the y-intercept)
$y=180x+2000$
or
$C(x)=180x+2000$