Find the surface area pls 20 pts since theres two

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

What is the slope of the line (-7,2) (4,6)

What is the length of the midsegment of a trapezoid with bases of length 15 and 25 ?