The answer is a. x=1 or x=11. Hope this helped.
Answer:
Option C 
Step-by-step explanation:
Given : Astronomers measure large distances in light years. One light-year is the distance that light can travel in one year or approximately 5,880,000,000,000 miles.
Suppose a star is 14.4 light years from earth.
To find : How many miles away a star is from earth?
Solution :
In 1 light-year the distance a light can travel is = 5,880,000,000,000 miles.
or =
miles
In 14.4 lights year the distance is 

or 
Therefore, Option C is correct - 
Vertical angles are angles opposite each other where two lines cross