Proving $f^{-1} (C) \backslash f^{-1} (D)= f^{-1} (C \backslash D)$ where $C,D \subseteq A$ and $E,F \subseteq B$ for $f: A \rightarrow B$
Proof of $f^{-1}(B_{1}\setminus B_{2}) = f^{-1}(B_{1})\setminus f^{-1}(B_{2})$