Minimize the following Boolean expressions using the properties and postulates of Boolean

algebra:

$f(a,b,c)\frac{?}{b}=ar(b*c)\frac{*}{b}ar(a*(\frac{?}{\text{b}\text{a}\text{r}}(b))*(\frac{?}{\text{b}\text{a}\text{r}}(c)))\frac{*}{b}ar(a*b*(\frac{?}{\text{b}\text{a}\text{r}}(c)))$

$f(a,b,c,d)=a*b*c*d+\frac{*}{b}ar(b)+a*b\frac{*}{b}ar(c)+a\frac{*}{b}ar(b)+a\frac{*}{b}ar(c)$