For the function $$f$($x$)=3-$x$,$ find each of the following. Question content area bottom Part $1($a$)$ f$($p$)$ enter your response here $($Simplify your$$ answer.$)$ Part $2($b$)$ f$(-$r$)$ enter your response here $($Simplify your$$ answer.$)$ Part $3($c$)$ f$($m$-1)$ enter your response here $($Simplify your$$ answer.$)$