$1.$ For following expression F$($x$,$y$,$z$)=\backslash$Sigma m $(1,2,4,7)$ use Shannon's expansions to

derive on implementation using $4$ to $1$ MUX $?($if necessary you can use logic gates$)$

$2.$Implement the circuit that performs $4-$bit addition$/$subtraction operations

using a full adder?