53,000 rounded to the nearest ten thousand

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 solution of this system of equation -7x+y=-20 9x-3y=36

Mrs. gehrke said cheddar weighs 16.8 pounds. he actually weighs 15.2 pounds. what is the percent error?