#### Answer

a. $E=352+42x$
b. $R(x)=130x$
c. more than $4000$

#### Work Step by Step

Let $x$ be in thousands of units (computer chips).
a.
$E(x)=352+42x$
b.
R(x)=px, where p is the price per unit
$R(x)=130x$
c.
P(x)=R(x)-C(x)
For a profit to be made, we need
$R(x) > E(x)$
$130x > 352+42x$
$88x > 352$
$x > 4$ (thousand)
more than 4000 chips need to be sold.