Explanation:
1. We can see that the two vertical lines are parallel. Since one angle is 80º, then the other side should be 100º, since the straight line is 180º.
2. If the angle on the right is 80º, then that means the angle with y and 40º add up to 100º.
3. 100º - 40º = 60º.
Our final answer: y = 60º
I hope this helps!