How can i find the expression value

Question

if P=(A+B) (B+C) =B+AC

Q=(A+C) (B+C)=C+AB

then find (P+Q)' or P'.Q' ?

Comments

P+Q = B+AC+C+AB = (B+C)+A(B+C) = (B+C)(1+A)= (B+C)

(P+Q)' = P'.Q' = (B+C)' = B'.C'

Answer 1

( P + Q )' = ( B + AC + C + AB)'

               =( B + AB + AC + C )'

               = ( B(1 + A) + C ( A + 1))'

               = ( B + C )'

               =  B' C'