Any ideas about these?

Prove that if $\displaystyle f$ is a function, $\displaystyle f^{-1}[A \cap B] = f^{-1}[A] \cap f^{-1} [b] $.

Also, prove that if $\displaystyle f$ is a function, $\displaystyle f^{-1}[A - B] = f^{-1}[A] - f^{-1} [b] $.

All of the B's should be capitalized, I'm not sure why it isn't coming out that way.