Please explain in an easy way how to evaluate the following.

Can someone pls ! pls answer all. no explanation needed..

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.

Find the condition that the zeros of the polynomial f(x) = x^3+3px^2+3px+r may be in a.p.