If $U=\{a, b, c, d, e, f, g, h\},$ find the complements of the following sets:

$A=\{a, b, c\}$

Taking the set of natural numbers as the universal set, write down the complements of the following sets:

$\{x: 2 x+5=9\}$

If $n(U)$ = $600$ , $n(A)$ = $100$ , $n(B)$ = $200$ and $n(A \cap  B )$ = $50$, then $n(\bar A  \cap \bar B )$ is 

($U$ is universal set and $A$ and $B$ are subsets of $U$)

Let $\mathrm{U}$ be universal set of all the students of Class $\mathrm{XI}$ of a coeducational school and $\mathrm{A}$ be the set of all girls in Class $\mathrm{XI}$. Find $\mathrm{A}'.$

If $U =\{1,2,3,4,5,6,7,8,9\}, A =\{2,4,6,8\}$ and $B =\{2,3,5,7\} .$ Verify that

$(A \cup B)^{\prime}=A^{\prime} \cap B^{\prime}$