(10 POINTS AND BRAINLEST)

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.

2x minus y equals 6, x plus y equals negative 3

What is the value of x? enter your answer in the box.