I posted this question earlier but I think I asked for too much so I am trying again and giving the answer I have, If you could tell me if it is correct, I would appreciate it.

Question

A sub is 7500 meters below sea level surfaces at rate of 80 meters per min. the depth of sub after m minutes is given by d(m) = -7500 +80m. give range and calculate domain.
80m = -7500
M = 90.3 domain
d = 80(0) -7500 = -7500 range
thanks for your help

Answer 1

The range is d = -7500 to 0 meters, since it cannot go higher than sea level, and cannot be lower than it started out, while rising.

The domain is m = 0 to 93.75 minutes.

Answer 2

d = 7500 - 80 t

domain = 0 to 7500/80 or 0 to 93.75

range = -7500 to 0

Answer 3

thank you drwls and damon, i really appreciate you help. ann