A submarine changes its position by - 7 meters every second. What is the change in the submarine's position after 300 seconds?

If you take - 7*300 is should equal - 2100

The submarine goes down 7 meters per second, so multiply 7 by 300 to see how many meters it went down.

7 * 300 = 2,100

So the submarines position is - 2,100 from the original position.