Help, I am stuck:
Find (A �� B) �� C, given A = {s, e, t}, B = {m, e}, and C = {f, r, e, e}.
A) { }
B) {s, e, t, m, f, r}
C) {e}
D) {s, e, t, m, e, f, r, e, e}
Sorry, we are unable to decode the special characters replaced by ? under Western encoding. If it is ∪, you type "& c u p ;" without the intevening spaces nor the quotes, and if it is ∩, you type "& c a p ;".
If all else fails, you simply write "union" or "intersection". At least we will know what the question is.