Final answer:
The result of =FIND("is", "Mississippi",3) is 5, as it returns the position of the first occurrence of the substring "is" in the word "Mississippi" starting from the third character, which is at the 5th position.
Step-by-step explanation:
The function =FIND("is", "Mississippi",3) in a spreadsheet or a programming context is used to locate the position of a substring in a text string, starting the search at a specific position. In this case, it's looking for the substring "is" in the word "Mississippi" starting from the third character. The first occurrence of "is" after the third character is at the 5th position. Therefore, the result of =FIND("is", "Mississippi",3) is 5.