Acar traveling at 36 m s starts to decelerate stanley it comes to a complete stop in 9 seconds what is its acceleration

The answer is -4 m/s². A car traveling at an initial velocity of 36 meter per second starts to decelerate and then suddenly the car comes to a complete stop which means the final velocity is zero. The acceleration can be calculated as
     acceleration = (final velocity - initial velocity) / time interval
                          = (0 m/s - 36 m/s) / 9s
                          = -4 m/s²

The equation of movement of the car is given by:
 
 Where,
 vf: final speed
 a: acceleration
 t: time
 vo: initial speed
 By the time the car stops we have:
 
 Substituting values we have:
 
 Clearing the acceleration we have:
 
 
 its acceleration is:
 

Ithink they do have the same properties just in less quantities i think