1. Let A={1,3},B={8,f,4,c},C={1,3,4,y},D={,{a,b,c},7},E={{a,{b,c}},{},4}, and U= {1,3,4,7,8,a,b,c,f,y} be the universal set. Write out each of the following sets. 1. AB 2. CA 3. AC 4. BC 5. E{{}} 6. A 7. C 8. 9. 10. CB D{} D{{}} 11. 12. Nes 13. 14. E{} E{{}} 15. 16. P(P({4}))E 17. AB 18. A 19. A{} 20. DE