Negation of the statement (p∧r)→(r∨q) is
~(p∧r)→∼(r∨q)
(~p∨~r)∨(r∨q)
(p∧r)∧(r∧q)
(p∧r)∧(~r∧~q)
we know that ~(p→q)≡p∧~q
∴ ~((p∧r)→(r∨q))≡(p∧r)∧[~(r∨q)]≡(p∧r)∧(~r∧~q)