Find the marginal revenue at x=10 using the equation R(x)=-x^2+80x

Is the answer 60?

3 answers

R(x) = -x^2 + 80x

R'(x) = -2x + 80

R(10) = -2(10) + 80 = -20 + 80 = 60

Correct
Yes! Thank you! I do have another question, though. The second part of the problem says to "compare R(11) -R(10) with that result." Does that mean that I derive it before plugging in 11 and 10 or...?
no, R(11) is just that. No derivative.

It's showing you how the marginal revenue can be approximated by noting the increase in revenue from one point to another.

R(11) = 759
R(10) = 700
∆R = 59, which is pretty close to R'(10)