Answer:
77 feet below sea level.
Step-by-step explanation:
Since y is the time the submarine is ascending, we can plug it in for y and find our answer. We can create an equation where D is the depth and y is time ascending: D = -230 + 17y
Substitute 9 for y:
D = -230 + 17(9)
D = -230 + 153
D = -77
The depth of the submarine after 9 minutes will be 77 feet below sea level. Hope this helps, and Brainly will be highly appreciated.