The marginal profit in dollars on Brie cheese sold at a cheese store is given by P'(x)=x(60x^2+30x), where x is the amount of cheese sold in hundreds of pounds. The "profit" is -$50 when cheese is sold.

a. Find the profit function. P(x)=
b. Find the profit from selling 300 pounds of Brie cheese.
Please help, I do not know where to begin

2 answers

P'(x) = 60x^3 + 30x^2
So,
P(x) = 15x^4 + 10x^3 + c

If you meant the profit is -50 when no cheese is sold, then P(0) = -50, and c=50. So,

P(x) = 15x^4 + 10x^3 - 50

Now plug in x=3 to find P when 300 lbs are sold.
kjb