Is 5x + 7 = 17 true false or open

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 i do this activity, is appreciated

To determine the number of deer in a forest a forest ranger tags 280 and releases them back