Pls help ASAP I need the answers to these questions :/

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.

Which shows the correct substitution of the values a,b and c from the equation 1=-2x+3x^2+1

How do the definitions, properties, and postulates you've learned about line segments, parallel lines, and angles to define the shapes of polygons