Design the following function using a $3$x$8$ decoder and external gates. $(4)$ F$1($x$,$y$,$x$)=($x$+$y$)$z$$ F$2($x$,$y$,$x$)=($x$+$y$)($x$+$z$)$ F$3($x$,$y$,$x$)=($y $+$ z$)($x$+$z$)$