Answer:
(-17 + 9) - 15
Explanation:
I think of below sa level as negative numbers, so 17 feet below sea level is -17. Then when he rises 9 feet that would be - 17 + 9. When he decends 15 feet to take another picture thats - 15. Then when you thing of pemdas addition goes first, so i just put parentases around -17 + 9 to get the expression (-17 + 9) - 15