Question: rewrite the negation of each of the following logical expressions...

Rewrite the negation of each of the following logical expressions so that all negations immediately precede predicates.

(a) ¬∀x(¬P(x) → Q(x))

(b) ¬∃x(P(x) → ¬Q(x))

(c) ¬∃x∀y(P(x, y) → Q(x, y))

(d) ¬(∃x∃y¬P(x, y) ∧ ∀x∀yQ(x, y))