Question 87293
Equilibrium is attained when supply equals demand.  Therefore
 D = -200p +35,000
 S = -p^2 +400p - 20,000

 -200p +35,000 = -p^2 +400p - 20,000


Set the quadratic equation equal to zero, and hope it factors!  If it does not, then you will have to use the quadratic formula or completing the square (or a graphing calculator!) to get the answer.


p^2 -600p+ 55000 = 0


This does NOT factor, so the quadratic formula, completing the square, or graphing calculator will be needed.  The answers I got with calculator (rounded to nearest whole number) are p=113 or p=487.


Life doesn't always come out even.  Nevertheless, the answers in math so often are "rigged" to work out that I am suspicious when they do NOT come out even.  So, check my work, and see if I am correct!!  Let me know if you need help solving the quadratic equation.


R^2 at SCC