Thinking Mathematically (6th Edition)

$(B\cap C)'=\left\{a, b, c, d, f, g\right\}$
$\cap$ represents intersection of sets. The intersection of two sets is a set that contains the elements that are common to both sets, Thus, $B\cap C = \left\{e\right\}$ RECALL: The complement of set A, represented by $A'$, is the set that contains all the elements of the universal set $U$ that are not elements of $A$. Thus, the complement of $B\cap C$ is: $(B\cap C)'=\left\{a, b, c, d, f, g\right\}$