Answer:
-800 + 250 = -550
-550 - 86 = -636
The sub is 636 feet below sea level.
Step-by-step explanation:
u start off with -800 since its 800 feet below sea level then you add 250 since it ascends 250 feet which gives you -550 then you subtract 86 since it descends that many feet. when you do all of that you get -636 which in wording would be 636 feet below sea level
