$x=75-7\mathrm{.}5p$ and $C(x)=81+0\mathrm{.}92x$

where $x$ is the number of bags that can be sold at a price of $p per bag and $C(x)$ is the total cost $($in dollars$)$ of producing $x$ bags.

a$)(2$ points$)$ Express the price $(p)$ as a function of the demand $(x)$

b$)(2$ points$)$ Find the revenue function

$(3$ points$)$ What is the marginal revenue at a production level of $36$ bags? Interpret your result.

d$)(5$ points$)$ Compute the break$-$even points $($round to the nearest unit$).$ Interpret your result.

$(3$ points$)$ What is the marginal profit at a production level of $36$ bags? Interpret your result.