Answer:
and 
Step-by-step explanation:
We are given that sin x+cos x=cos 2x
We have to solve the given equation for 

Because 








Tan x is positive in I and III quadrant
In III quadrant angle
replace by 
Therefore, 

Answer:
-6
Step-by-step explanation:
3n = n² - 54
n² - 3n - 54 = 0
n² - 9n + 6n - 54 = 0
n(n - 9) + 6(n - 9) = 0
(n - 9)(n + 6) = 0
n = 9 , -6
hope this helps
It should be c really hope this helps and im right have a blessed day:)
25.7 because that is the answer