If

C$($x$)=13,000+500$x $1\mathrm{.}2$x$2+0\mathrm{.}004$x$3$

is the cost function and

p$($x$)=2,9006$x

is the demand function, find the production level $($in units$)$ that will maximize profit. $($Hint: If the profit is maximized, then the marginal revenue equals the marginal cost.$)$