A chemical manufacturer sells sulfuric acid in bulk at a price of?

$100 per unit. The total daily production cost C in dollars for x units is given by:
C = 100,000+50x+.0025x^2.
The total daily production capacity is at most 7,000 units(no more than this)

a) How many units of acid must be manufactured and sold daily to maximize profits?
b) would it benefit the manufacturer to expand the daily production capacity over 7,000 units??