Answer:
Step-by-step explanation:
-3x - 21 + 2x -4
-x - 25
-(x + 25)
 
        
             
        
        
        
9514 1404 393
Answer:
   21.25 seconds
Step-by-step explanation:
In miles per second, the speed of the jet is ...
   (720 mi/h)/(3600 s/h) = 1/5 mi/s
The speed of the sound is the same:
   (1 mi)/(5 s) = 1/5 mi/s
Then the rate of closure between the airplane and the sound is ...
   (1/5 mi/s) +(1/5 mi/s) = 2/5 mi/s
To find the time required to close a gap of 8 1/2 miles, we can use the relation ...
   time = distance/speed
   time = (8.5 mi)/(0.4 mi/s) = 21.25 s
The pilot will hear the thunder 21.25 seconds after the flash.
 
        
             
        
        
        
Answer: A ≈ 74.35
Step-by-step explanation: Explanation below.
 
        
                    
             
        
        
        
Its I and IV  :).kbiyhtrhirthrkhnrihrthn