Darla and dave leave school each day at 2: 00 p. m. on their bikes and travel in opposite directions. if darla rides at a constant rate of 12 kilometers per hour and dave rides at a constant rate of 14 kilometers per hour, after how many hours are they 65 kilometers apart?

a 1.25
b. 2.5
c. 5
d. 6.5

2.5 hours

Step-by-step explanation:

12 + 14 = 26

65 / 26 = 2.5

Hope this helps you! :)

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!