A submarine at -28 feet dives 40 feet. What is the submarine's elevation after the dive?

Since it's going down, subtract another 40 feet:

-28-40

68 -68

-80

To find the submarine's elevation after the dive, you can add the change in depth from the initial position to the dive depth.

The initial depth of the submarine is -28 feet and it dives 40 feet. Adding these two values will give us the final depth:

-28 feet + 40 feet = 12 feet

Therefore, the submarine's elevation after the dive is 12 feet.