#### Answer

$x=500, P(x)=140x-70000$

#### Work Step by Step

Given: $C(x)=105x+70000$ and $R(x)=245x$
After equating the given two equation, we get
$140x=70000$
or, $x=500$
Now, $P(x)=245x-(105x+70000)$
or, $P(x)=140x-70000$
Thus, $x=500, P(x)=140x-70000$