Hello! Can anyone explain how to do this question? I am not sure how the answer is C.

Focus on the triangle. Can you write the other two angles in terms of z and x respectively?

I understand that one of the angles will be x in the triangle because they are opposite angles so would be the same. However, I am confused on the z part.

We have a straight line. What property can you use then?

Ohh so would z=180-w. Where W is the other angle. So 180-w-x would give us y?

Correct. You now have a triangle whose angles are 180 - z, x and y. What do they sum up to?

We have

(180 - z) + x + y = 180

Simplifying,

180 - z + x + y = 180

x + y = z

y = z - x → Quantity A and B are the same.