Could someone please explain how to solve this?

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.

The graph below represents the number of dolphins in a dolphin sanctuary. select all the key features of this function.

Find the distance between (0,5) & (-4,2)