The value of cos B is 12/13
The answer should be x=60. ABD are an equilateral triangle all the angles must add up to 180. 60*3=180. Also if you have a protractor you can measure the angle C, the 60 degrees part and measure it against A, D and B. Hope this helps.
Answer:
x=4.5
Step-by-step explanation:
Given the equation
, we simplify as:

#We further simplify as multiples of 9(divide by 9 to solve for x):

Hence, from our simplification the equation has the same value as x=4.5