Question 231428
What you have is a quadratic formula in the form of ax^2 + bx + c where:


a = -10
b = 3500
c = -66000


Since a is negative, this quadratic equation opens downward.


The max point is at x = -b/2a


That would be at x = -3500/-20 = 175.


When x = 175, y = -10*175^2 + 3500*175 - 66000 = 240250


Maximum profit attained is $240250.


This happens when 175 cars are sold.


graph of this equation looks like this:


{{{graph(400,400,-50,350,-100000,300000,-10x^2+3500x-66000,240250)}}}


As can be seen, the graph peaks at x = 175.