The following is all the information needed:
There are, of course, all the basic rules of logic and set identities to be considered.
The Attempt at a Solution
Not really sure how to attempt this one, to be honest. I know that (A ⊆ B) can be written with a quantifier and is equivalent to ∀x[xϵA ⇒ xϵB] but I'm really not sure how to apply this information properly.
Thanks, guys. :)