it is known that the cost function of an enterprise is C = q3-9q2 + 30g + 25, where C is the cost (unit: thousand dollars), q is the output (unit: T), and the minimum value of average variable cost C (unit: thousand dollars) is obtained.

hello from mrbilldoesmath!

answer:

25x^2 + 90x + 84

discussion:

mn(x) = m(n(x)) = m( 5x + 9) =

(5x + 9)^2 + 3 =>

25x^2 + 90x + 9^2 + 3 =

25x^2 + 90x + 84                 (as 9^2 = 9*9 = 81)

which is the second choice

regards,  

mrb

p.s.   i'll be on vacation from friday, dec 22 to jan 2, 2019. have a great new year!

first one because it can't have a fraction in it

step-by-step explanation: