190 x 15 = square feet?

Write an inequality and solve each problem.for exercises 11 and 12, interpret the solution.

Suppose that the price p, in dollars, and the number of sales, x, of a certain item follow the equation 4 p plus 4 x plus 2 pxequals56. suppose also that p and x are both functions of time, measured in days. find the rate at which x is changing when xequals2, pequals6, and startfraction dp over dt endfraction equals1.5.

Can anyone explain to me how to do this? anything will .