What is the rate of change of y = 1/2x

Asap 25 pts + brainlest to right/best answer

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.

Find the midpoint m of z1=(8+5i) and z2=(12+3i)