Here is another one that I am having problems with.

The cost (in dollars) of producing x items is

C (x) = 4000 - 3x + (X^2 1000)

If the items are sold for $4 each, find the value of x that maximises theProfitand find the maximum profit.

I have figured out the equasion

Profit = P = 4x - (4000- 3x + (X^2 1000)

I tried to put it into my graphics calculator, and get the value for the max profit but its a linear equasion.

Thanks in advance for any help

P.S apologies in advance, I do not know how to put maths equasions into computers... maybe my next question should be about that!