Answer:
x + y = 170
Explanation:
360 = 110 + x + y + 80
x + y = 360 - 110 - 80
x + y = 170
To understand this, take scissors and look at the angles how they change when you change the angle... there are always just TWO different angles and each of the angle has its exact counterpart on the opposite side. Now look again at this illustration and you will get it!
Another information, sum of all the angles inside of any rectangle is always 360 degrees!