20. How many minutes would it take a train to travel 90 kilometers at a constant speed of 120 kilometers per
hour?

F. 30
G. 40
H. 45
J. 80
K. 90

45

Step-by-step explanation:

Every 15 minutes, 30 kilometers are passed by.

15/60 = 1/4 hour

30/120 = 1/4 speed

i dont know

step-by-step explanation:

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!