Suppose the rate of change of the unit price p of video boards is p'(x) = 1500x (x2+9)3/2 where x is the number of hundreds of video boards that the supplier will make available to the market daily and p is in dollars. Find the supply equation p(x) for the video boards if the quantity the supplier is willing to make available is 400 video boards when the unit price is 390 dollars.