I will give the brainiest a stack of poles has 28 in the bottom row, 27 poles in the next row, and so on, with 5 poles in the top row. how many poles are there in a stack?

needs a specific velocity as well as a thrust to reach the desired height above the earth's surface. The velocity and the thrust of a satellite launch vehicle depend

There are 396 poles in the stack.

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!