I need help plz

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.

Math it's appreciated. (picture provided)

On the day a coffee shop first opened, it had 140 customers. 65% of the customers ordered a large coffee. how many customers ordered a large coffee? enter your answer in the box.