Answer
700
(copies need to sold to break even)
Work Step by Step
Breakeven occurs when $P=0$, or $R(x)=C(x)$.
The break-even point is the number of items $x$ at which break even occurs.
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Using the result of part (a), $P(x)= 0.10x-70,$
$P(x)=0$
$0.1x-70=0$
$0.1x=70\qquad/\div 10$
$x=700$
The break-even point is 700 (copies sold)
