algebra
posted by ann .
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.
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

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. 
d = 7500  80 t
domain = 0 to 7500/80 or 0 to 93.75
range = 7500 to 0 
thank you drwls and damon, i really appreciate you help. ann