## Thinking Mathematically (6th Edition)

$(A\cup B)'=\{c, d, e, f\}$
We are given: $U = \{a, b, c, d, e, f, g, h\}$ $A = \{a, g, h\}$ $B = \{b, g, h\}$ $C = \{b, c, d, e, f\}$ We need to determine $(A\cup B)'$ The union of sets $A$ and $B$ ($A\cup B$) is a set that has all the distinct elements of both $A$ and $B$. $A\cup B=\{a, b, g, h\}$ The ($'$) outside of the bracket indicates that we need a complement set: the result set should contain the elements in the universal set $U$ that are not in $(A\cup B)$. $(A\cup B)'=\{c, d, e, f\}$