I need help with unions, intersections, and complements involving 2 sets

Here, we want to get the set resulting from the given set operations
a) This set is the complement of the intersection of the subsets C and D
The intersection refers to that set that has its members as the elements present in both subsets
The intersection here is;
[tex]\mleft\lbrace8\mright\rbrace[/tex]Now, the complement here are the other elemnts present in the universal set
We have this as;
[tex]\mleft\lbrace1,2,4,7\mright\rbrace[/tex]b) Here, we want to get a union
The complement of set C are the elements that not present in set C but are in the universal set
So, the union here is are the list of elements in both set, without no repetitions
[tex]\begin{gathered} C^{\prime}\text{ = }\mleft\lbrace2,4\mright\rbrace \\ D\text{ = }\mleft\lbrace2,8\mright\rbrace \\ C^{\prime}\text{ U D = }\mleft\lbrace2,4,8\mright\rbrace \end{gathered}[/tex]