This is a question from the Discrete Mathematics question from Kenneth Rosen book.
I didn't understand the question and thus I am confused how to begin with question. Below is the question from the book.
Establish these logical equivalences, where x does not occur as free variable in A. Assume that the domain is nonempty.
a) ( ∀x P(x)) ∨ A) ≡ ∀x (P(x) ∨ A)
Also what does "x does not occur as free variable in A" mean. Thank You.