Here are two number machines, A and B. Input
Output
А
x 5
3
B.
x 3
+ 8
Both machines have the same input, x.
Work out the input that makes the output of A three times the output of B

you are saying it as if a fact, not a question, but yes, you would be correct? ; )

step-by-step explanation:

attachment?

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!