I have no idea how to solve this. Any help would be appreciated! The statement is
For any sets A, B, and C that are subsets of a universal set U, A-(B∩C)=(A-B)∪(A-C).
Or use the basic definitions: if x is in $\displaystyle A-(B\cap C)$ then x is in A but not in $\displaystyle B\cap C$. That, in turn, means it is either NOT in B or NOT in C.
case 1: x is in A but not in B. Then it is in $\displaystyle A\cap B$.
case 2: x is in A but not in C. Then it is in $\displaystyle A\cap C$.