PLEASE HELP ( multiple choice answers )

B

Step-by-step explanation:

Since the triangle is a 30-60-90 triangle, we can use a shortcut to find the answer.

Our sides are 10 and y, the hypotenuse is x, and theangle we are given is 60 degrees.

As such, we know that:

a = 10, since that side length is opposite the 30 degree angle.

y = a = 10

x = 2a = 2(10) = 20

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!