# Math Help - Profit maximization

1. ## Profit maximization

I keep getting my derivative at -.12x^2-10.8x-1200
with zeros at -154.659, 64.659 I dont know if thats right though

here is the question:

If C(x) = 13000 + 400x - 0.6x2 + 0.004x3 is the cost function and p(x) = 1600 - 6x is the demand function, find the production level that will maximize profit. (Hint: If the profit is maximized, then the marginal revenue equals the marginal cost.)

2. P(x)=Revenue function - cost funtion

Take the derivative and set equal 0

3. I did that but I get -.12x^2-10.8x-1200=0 which doesnt do anything for me

4. What is your revenue function?