Answer: Check explanation.
Step-by-step explanation: I think its 0. Not sure. Hope this helped!
I and III seem to be correct, II doesn't because, for example, if x = w = z = t = 70 and y = u = 40, then all three pairs of vertical angles in the figure have equal measure and the given condition x + y = u + w stands. But it means y is not equal to w.
1+7/11 = 11/11+7/11 = 18/11
2+1/2 = 4/2+1/2 = 5/2
(18/11)/(5/2) = (18/11)*(2/5) = 36/55
Suppose we choose

and

. Then

Now suppose we choose

such that

where we pick the solution for this system such that

. Then we find

Note that you can always find a solution to the system above that satisfies

as long as

. What this means is that you can always find the value of

as a (constant) function of

.