I need help please !

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.

In which form is the following function written? y = - 2(x – 3)(x + 5)

Simplify (1/2)4th power a. (1/16) b.(1/8) c.(1/4)