9 is the greatest common factor correct answer. First you had to find prime factorization of 9: 1, 3, 9, 3²=3*3=9. And then, you had to find prime factorization of 27: 1, 3, 9, 27, 3³=3*3*3=27. The greatest common factor of 9 and 27 is 9 is the final answer. Hope this helps! And thank you for posting your question at here on brainly, and have a great day. -Charlie
