Implement the following Boolean functions using:

$(1)$ Decoder and NAND gates

$(2)$ Two MUX for each of the functions $($control variables A$,$ B for f$1,$ control variables B$,$ C for f$2)$

$(3)$ ROM indicates the size of the ROM $($e$.$g$.2^{n}m$ ROM$)$

$f_1(A,B,C)={\displaystyle \underset{?}{\overset{?}{}}}(0,2,3,5,7)$

$f_2(A,B,C)={\displaystyle \underset{?}{\overset{?}{}}}(1,3,5,7)$