SOLUTION: Good Afternoon, Sam here. I am having a terrible time trying to solve this story or word problem. The trouble I am having is getting the exact answer as the book shows. Could someo

Question 362030: Good Afternoon, Sam here. I am having a terrible time trying to solve this story or word problem. The trouble I am having is getting the exact answer as the book shows. Could someone who is an expert is this area please show me, by covering all steps how I would attack this type of problem.
Section 11.5, #9
Directions: Solve
The total function p(x) for a company producing x thousand units is given by
P(x)=-〖2x〗^2+28x-80 (it should be -2x squared)
Find the values of x for which the company makes a profit. [Hint: company makes a profit when P(x)>0].
the answer my textbook provides is: x is between 4 thousand units and 10,000 units.
I have no idea how to even get started, or what steps I should use to get the correct answer. Your help is greatly appreciated.
Answer by edjones(8007) (Show Source): You can put this solution on YOUR website!
P(x)=-2^2+28x-80
-2^2+28x-80=0
x=3
when x>3 then P(x) is positive to infinity.
Did you copy the equation correctly?
.
Ed

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