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

$\{x: x+5=8\}$

Let $U=\{1,2,3,4,5,6,7,8,9\}, A=\{1,2,3,4\}, B=\{2,4,6,8\}$ and $C=\{3,4,5,6\} .$ Find

$(A \cup C)^{\prime}$

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

$\{ x:x$ is an even natural number $\} $

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

$\{ x:x$ is a natural number divisible by $ 3 $ and $5\} $

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

$\{ x:x$ is a prime number $\} $