Answer: 3 feet underwater
Step-by-step explanation:
The scuba diver starts off 12 feet underwater. The diver then increases their depth by 9 feet. This is because the diver ascends 5 feet and another 4. That adds up to 9, so you subtract 12 by 9.
✅ Just add the changes in depth and then add/subtract it from the starting depth, which is 12 feet.