Answer
(A∪B)' = {4,6}
Work Step by Step
U = {1,2,3,4,5,6,7}
A = { 1,3,5,7}
B = {1,2,3}
A∪B represents all the elements of A and the elements of B that are not present in A.
Therefore the elements of A∪B are {1,2,3,5,7}.
(A∪B) = {1,2,3,5,7}
The set (A∪B)' represents the elements of 'U' that are not present A∪B
Because the elements of A∪B i.e. 1,2,3,5,7 that is not present in (A∪B)' = {4,6}
(A∪B)' = {4,6}