Answer
A' = {c,d,e}
Work Step by Step
U = {a,b,c,d,e,f,g}
A = {a,b,f,g}
Find A'
Set A' includes all the elements in 'U' that are not in set A.
Since set A contains a,b,f,g so these elements cant be in set A'
Therefore the elements of set A' are c,d,e
Therefore A' = {c,d,e}