Question $2$: $(24$ points$)$ Simplify the following expressions to their minimal expressions using Boolean algebraic manipulation

Part a$)\stackrel{}{x}*(\frac{?}{\text{b}\text{a}\text{r}}(y)\frac{+}{b}ar(z))*(x+y\frac{+}{b}ar(z))$

Part b$)*b*(\frac{?}{\text{b}\text{a}\text{r}}(d)\frac{+}{b}ar(c)*d)+b*(a+*c*d)$