A12 foot laser tests against a brick wall at angle of 60 degrees which expression gives the value of x the height on the brick wall where the ladder rest ?

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.