$6\mathrm{.}4$ Repeat problem $6\mathrm{.}3$ for the function $f\frac{?}{b}=ar\frac{(w{)}_2}{b}ar(w{)}_3+w_1{w}_2.$

$*6\mathrm{.}5$ For the function $f(w_1,w_2,w_3)={\displaystyle \underset{?}{\overset{?}{}}}m(0,2,3,6),$ use Shannon's expansion to derive an implementation using a $2-$to$-1$ multiplexer and any other necessary gates.