What is the average rate of change for the function f(x) from x=1 to x=3

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.

Round to the nearest ten thousandth.i dont get this

Hakeem puts $59 from each paycheck into his savings account. he gets paid every two weeks or 26 times per year. his goal is to save $1500 this year. will hakeem reach his goal? explain your answer using words, a model and equation.