Help me please I need help

Use the 45-45-90 rule.

Step-by-step explanation:

Based on angle A being 45 and angle B looking like its 90 degrees, angle C will be 45 degrees and so you'd use the 45-45-90 rule, which is a special right triangle. The 45 degrees sides are x and the hypotenuse is x. It will be easier if you look it up to see a graphic of it, but I'm pretty sure that both sides CB and AB are 6 based on this rule.

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!