Please help me, ASAP.. Ummm?!!

What are the domain and range of the function? f(x) = -4 (sqrt)x

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.

If sec theta = 5/3 and the terminal point determined by theta is in quadrant 4, then