Answer :

The best thing to do here is simply to list all of the actors for each number and this will let you see the GCF, 28- 1,2,4,7,14,28 42- 1,2,3,6,7,14, 21, 42 Therefore, you're correct and 14 is the GCF Hope this helps :)
You are correct the Greatest Common Factor of 28 an 24 is 14.