These equations are found in any physics text.  Practice your algebra and isolate the different variables in these equations.

Remember, if an object is starting from rest (zero m/s) then Vo=0 and if an object comes to rest, then Vf=0
DX=((Vo+Vf)t)/2



Acceleration Defined: a=Vf-Vo/t ==>Vf=Vo+at   and  Vo=Vf-at  and  t = Vf-Vo/a

DX=Vo(t)+at²/2

Vf²=Vo²+2aDX
HOW DO WE GET THESE EQUATIONS ???


Xf-Xo=Vt, where v=average velocity, or Vavg
Vavg=(Vf+Vo)/2  because to average is to sum and divide by # total
if we insert second equation into first one (where V is),
we get Xf-Xo=((Vf+Vo)t)/2
introduce 2nd equation (from line 2 above)Vf=Vo+at  insert this into third equation above, 
(1 box above this one)
get Xf-Xo=((Vo+at+Vo)t)/2
clean it up a bit
get, Xf-Xo=(2Vot+at²)/2
which is the same as 2Vot/2 + at²/2
so we cancel out a couple of 2's,
and get Xf-Xo=Vot+at²/2
quite often we are asked for some final position, so physics books usually write the equation as
Xf=Xo+Vot+at²/2