I think x=24 but not sure
Y=Mx+B -> slope intercept form
The answer would be -3y=-5x-9
Divide the -3 on both sides and you get
y=5/3x+3
The submarine is now 617.5 feet below sea level, or at -617.5 feet. the temperature is now at 65 9/20
you have to add the first values with the second values :)