$ P \vee q \Rightarrow(\sim r \vee p )$
$\equiv \sim( p \vee q ) \vee(\sim r \vee p ) $
$\equiv(\sim p \wedge \sim q ) \vee( p \vee \sim r )$
$\equiv[\sim p \vee p ) \wedge(\sim q \vee p )] \vee \sim r$
$\equiv[\sim q \vee p ) \vee \sim r$
Its negation is $\sim p \wedge q \wedge r$