Can someone me i don’t know if you got to have to add 4 numbers or 2 numbers

What is the distance between the points (2 -3) and (-6 4) on the coordinate plane

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.

Ineed the question and choices are in the