NEED ANSWERS FASSSTTT!!

If there are 12 moths and some have 31 days and others have 30 days how many have 28 days?

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.

How to find the exponential function y=ca^x, with points (1,2) and (2,1)