Answer: 127
Explanation:
Vertical Angles mean that those 2 angles are equal. 
Thus, 
You set the two equations equal to each other and solve for the value of x. 
5x+12 = 6x-11
x = 23
Next 
Once you find the value of x you need to plug in 23 back into any equation to get the value of your angle. 
5(23) + 12 = 127