Question 2: Suppose that a company that spends $x on advertising sells $s of mer

Question 2:
Suppose that a company that spends $x on advertising sells $s of merchandise where s(x)=-3x^3+270x^2-3600x+18000 and s and x are both in thousands of dollars.
a) find the value of x that maximizes the rate of change of sales
b) what is the significance of the value of x in (a)?Question 3:
A bookstore has been offering a bestseller at $30 per copy and it has been selling 200 copies per month at this price. The store estimates that for each $2 decrease in price 20 more books will be sold per month.
a) find the demand function assuming a linear model
b) using the demand function in (a) find the price of each copy which will generate maximum revenue. Give maximum revenue.