Question

Let U = {1, 2, 3, 4, 5, 6, 7, 8, 9}, 

A = {1, 2, 3, 4}, 

B = {2, 4, 6, 8} and 

C = {3, 4, 5, 6}. 

Find: (B – C)’

Answer 1

B – C is defined as {x ϵ B : x ∉ C} 

B = {2, 4, 6, 8} 

C = {3, 4, 5, 6} 

B – C = {2, 8} 

Now, (B – C)’ = U – (B – C) 

U = {1, 2, 3, 4, 5, 6, 7, 8, 9} 

B – C = {2, 8} 

(B – C)’ = {1, 3, 4, 5, 6, 7, 9}.