$3\mathrm{.}3$ Find the complement of each of the following Boolean expressions $($find $F^{\text{'}})$ and simplify algebraically.

a$.F(A,B,C,D)=[A+(BCD{)}^{\text{'}}][(AD{)}^{\text{'}}+B(C^{\text{'}}+A)]$

b$.F(A,B,C,D)=A{B}^{\text{'}}C+(A^{\text{'}}+B+D)(AB{D}^{\text{'}}+B^{\text{'}})$