If the speed of an object from 121m's to 98m's during a time interval of 12s what is the accelerations of the object?

Answer 1

Average acceleration is a net change in velocity over a corresponding change in time.

Your velocity went from 65 to 98 m/s - that's a positive change (gain) of 33 m/s.
the time interval was 12 s.

+ 33/12 m/s/s = + 2.75 m/s/s.

Answer 2

Average acceleration during a period of time is (change in speed) divided by (time for the change).

A = (98 - 121) / (12) = 23/12 = -1.9167meters/sec2 average during the 12 seconds.

Answer 3

-1.9166... m/s2