$$(p'\vee q)\Leftrightarrow (p\Rightarrow q')$$
$$\equiv$$
$$ (p'\vee q)\Leftrightarrow (p'\vee q') $$
$$\equiv$$
$$[(p'\vee q)\Rightarrow (p'\vee q')] \wedge [(p'\vee q')\Rightarrow (p'\vee q)]$$
$$\equiv$$
$$[(p'\vee q)'\vee (p'\vee q')] \wedge [(p'\vee q')' \vee (p'\vee q)]$$
$$\equiv$$
$$[(p\wedge q')\vee (p'\vee q')] \wedge [(p\wedge q) \vee (p'\vee q)]$$
$$\equiv$$
$$\ldots$$