Can you please tell me the answer for 8m/.9/12m=

Hi my sisters and brothers can tell me the answer because i don’t understand the question

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.

Iwill give you ! what is the measure of ∠v ?