Hi! I just need somebody to explain how this is done. I don’t understand the process of this well and I cant find many videos that explain it. thanks!

Exact form: x =

Rounded to the Nearest Tenth: x = 12.9

Step-by-step explanation:

In the right-angled triangle, we can use the trigonometry functions to find the length of a side or a measure of an angle

In the given figure

∵ ∠C is the right angle

∴ ΔACB is a right triangle

∵ m∠B = 57°

∵ AC = 10.8

∵ AC is the opposite side of ∠B

∵ AB is opposite to the right angle

∴ AB is the hypotenuse

∵ AB = x

→ We can use the function sine to find x

∵ sin∠B =

∴ sin∠B =

→ Substitute the values of ∠B, AC, and AB in the rule of sine above

∴ sin(57°) =

→ By using cross multiplication

∵ x × sin(57°) = 10.8

→ Divide both sides by sin(57°)

∴ x =

∴ x = 12.87752356

→ Round your answer to the nearest tenth

∴ x = 12.9

Exact form: x =

Rounded to the Nearest Tenth: x = 12.9

answer: 59

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!