Someone answered before but I couldn’t get the link he posted anyone else know?

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.

How do you solve a question like this?

Give all possible names for the line shown.calculation tip: lines can be written with either point first.