
Doug C. answered 10/13/22
Math Tutor with Reputation to make difficult concepts understandable
So since vertical angles are equal you can set their respective algebraic expressions equal to each other.
x+12=6x - 8
Now solve for x. If what appears next is confusing, post a comment to this answer.
x - 6x = -8 - 12
-5x = -20
x=4.
If x = 4, then x+12 = 4+12 = 16.
And also, 6x-8 = 6(4)-8 = 24-8 = 16.
So each vertical angle has a measure of 16 degrees.