A submarine is descending to examine the seafloor 2,100 feet below the surface. It takes the submarine 2 hours to make this descent. Write an equation to represent the relationship between the submarine's elevation and time using x as the number of hours, and y is the elevation.
Another submarine’s descent can be represented as y=-240x , where y is the elevation and x is time in hours. How long will it take this submarine to make the descent?
It is also going down the same distance as the first submarine in the first problem.