For this problem i got -4.0 but i don't think it is right . problem - 4.9 + z = -9 . // tell me how you did it and to whoever if you tell how you did it , it will make it much easier for me to know how to do other ones : )) 15

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!