How come (A' n B') n [(A u C) n (B' n C')] = (A' n B') n (A u C) n (B' n C') ?

Is it by the commutative laws ? THese brackets and parantheses are really confusing me .

Isnt that by distributive

(A' n B') n [(A u C) n (B' n C')] = [(A' n B')n(A u C)] n [(A' n B') n (B' n C')]

and it doesn't equal to (A' n B') n (A u C) n (B' n C') from the above .

I really thank you for your time and effort to explain this to me .