Answer: 7
Explanation:
The merge of two sets is a new set that has all the elements that are at least in one of the sets w/out repeating elements. The intersection of two sets is a new set that has the elements in both of the sets because {1, 2, 3}∩{2, 3, 4}={2, 3}. In this case the only common element is number 7 so: {4, 7, 10, 13, 17} ∩ {2, 5, 7, 9} = {7}.