You may recognize that ∆WYZ is a 3-4-5 right triangle. Without any work, then
c = 5
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If you don't remember that a right triangle with legs 3 and 4 has a hypotenuse of 5, you can compute it using the Pythagorean theorem.
c² = 3² + 4²
c² = 9 + 16 = 25
c = √25 = 5
Y = 8
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Hey there!
Basically it wants you to add 3 and 8 from each other, what ever the answer to that part, you multiply the result by 9
Here this is what i meant

Or you could do this method too!

They both give you the result of 
So, I am assuming your expression would look like this: 
Good luck on your assignment and enjoy your day!
~
Answer:
\
Step-by-step explanation:
Answer: 54
<u>Step-by-step explanation:</u>
replace "a" with "-2" in the g-equation
g(a) = a² - 4a + 42
g(-2) = (-2)² - 4(-2) + 42
= 4 + 8 + 42
= 54