Answer
$500$ units
Work Step by Step
Given,
$C(x) = 105x+70000$
$R(x) = 245x$
To find break-even point,
$C(x) = R(x) $
$ 105x+70000=245x$
$70000=245x-105x$
$70000=(245-105)x$
$70000=140x$
$x = \frac{70000}{140} = 500$
$500$ units must be sold to break-even.