Question 1102332
Well the marginal profit function is a derivative of the P(x). So, first take the derivative of the P(x) to obtain P'(x).

Let P'(x) = D(x) (because for some reason the equation editor won't let me work with apostrophes)

Thus, {{{D(x) = -2x+ 150}}}

Now you want to find the marginal profit when x = 10. To do this, plug in x =10 to the function that just got differentiated.

{{{D(x) = -2(10) + 150}}}

Simplify and obtain

{{{D(x) = 130}}}

130 is your final answer, the marginal profit.