I need help with this problem. this is what I got so far:
P(x)=12x-(x^2/500)-680-4x-0.01x^2
P'(x)=12-0.004x-4-0.02x
P'(x)= -0.024x-8
x=8/0.024
My book says x=8/0.024 which somehow become 1000/3. They are the same when solved but how did they come up with 1000/3?
multiply numerator and denominator by 1000/8
