+9665 Since you didn't reply, I will assume that it denotes the symmetric difference \(A \oplus B = (A \cup B) - (A \cap B)\).
First, \(C - B\) is just the collection of elements in C that is not in B, i.e., \(C - B = \{2, 4\}\).
Now, we calculate \(A \oplus (C - B) = A \oplus \{2 ,4\}\).
Note that \(A \cap \{2, 4\} = \varnothing\) since the two sets do not have common elements. Then \(A \oplus \{2, 4\} = A \cup \{2, 4\} = \{1,2,4,5,6,8\}\).
Hence, we have \(A \oplus (C - B) = \{1,2,4,5,6,8\}\).
