Answer:
{3, 4, 6, 7, 8}
Step-by-step explanation:
For sets U = {1, 2, 3, 4, 5, 6, 7, 8}, A = {1, 2, 5, 6}, and C = {1, 2, 3, 4, 5}, you want the set {A∩C}'.
A∩C
The set A∩C contains the elements that are common to both sets. Those are {1, 2, 5}.
{A∩C}'
The set of interest contains the elements of U that are not in A∩C. Those are ...
{3, 4, 6, 7, 8}
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Additional comment
DeMorgan's theorem tells us the desired set is equivalent to A'∪C', or {3, 4, 7, 8}∪{6, 7, 8}. That, too, is ...
(3, 4, 6, 7, 8}
