I've never seen anyone use x and 𝑥 for different things
Yeah, me neither. I have had situations where I needed to distinguish between u, v, nu, and upsilon though. I had to be very careful with my handwriting that day...
They also wouldn't want to be ambiguous. If I was trying to write this problem the a, b, c... would get replaced by something like a_1, a_2,..., a_26 to be clearer. This problem works as a fun gotcha but isn't something that would come up in the real world.
So your argument is that in the list "a, b, c, ..., z" the "..." Bit could be anything and we have no way of knowing what's there and therefore the problem is unsolvable? Or what are you saying exactly?
Yes. The variables a, b, c, and z must have a stated correlation. Variable names do not implicitly have any relation between them. Ellipses work for numbers because a series of 1, 2, 3 ... 100 can be inferred using the rules of mathematics. A series of a, b, c ... z cannot; the series can only be inferred using the rules of the English language.
so is the word "simplify". I guess we'll never know what they mean by that because if you pretend you don't speak English, then there's no way of knowing!