A fertilizer producer finds that it can sell its product at a price of p=5000-1.0x dollars per unit when it produces x units of fertilizer. The total production cost (in dollars) for units is c(x)=150000+1250x+0.25x^2

If the production capacity of the firm is at most 1000 units of fertilizer in a specified time, how many units must be manufactured and sold in that time to maximize the profit?

x=? units