What is the area of a regular octagon when the apothem is 7 cm. round to the nearest tenth

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.

What is sin 7x/4 ? i need on this urgent trig

Solve 3x-18=2y and 5x-6y=14 by elimination or substitution . show all !