# Find complement of given expression using Boolean algebra

Find the complement of $$xy(y+y'z) + x'z$$

I solve this problem but get 3 different solution by using 3 different methods (rules of boolean algebra)

Solution that I get each time

1. $$\quad x'z'+xy'+y'z'$$
2. $$\quad xy+xyz'$$
3. $$\quad y'z'$$
• xy(y + y'z) + x'z = xyy + xyy'z + x'z = xy + x'z. Jun 23 at 5:07
• @MikeSmith please read the question again (find complement) Jun 23 at 5:08