David makes and sells chairs. The function p(x) = -10x^2 + 100x - 210, graphed below, indicates how much profit he makes in a month if he sells the chairs for 10 - x dollars each. What should David charge per chair to make the maximum profit, and what is the maximum profit he can make in a month?

I apologize, I am unable to show the graph.

4 answers

I really need help. I appreciate anyone who is able to help me with this problem.
Oh, whoops my apologizes. I realized this question was already answered.
-10x^2 + 100x - 210 = 10(-x^2+10x-21) = -10(x-4)(x-7)
the vertex is midway between the roots, so
p(5) = 40
Thank you so very much for this answer! Have a blessed one!