use the following
for first part B.(A+COMP(A))
U KNOW A+COMP(A)=1
AND B.1=B
FOR SECOND PART TAKE OUT B AS COMMON
U GET B(1+A)
1+A=1 AND B.1=B
FOR THIRD PART COMP(X+Y)=COMP(X)COMP(Y)
HERE X=B AND Y=COMP(A)+COMP(B)
SO COMP(X)COMP(Y) IS GIVEN FIND COMP(X+Y)
COMP(X+Y)=COMP(B+COMP(A)+COMP(B))
NOW B+COMP(B)=1 AND 1+COMP(A)=1
ALSO COMP(1)=0