In Mortal Kombat 9 (2011 version) for the PS3 and Xbox 360, each character has multiple fatalities that they can perform at the end of the match if your opponent is defeated.
This is the list of all finishers (two fatalities, one babality, and one stage fatality) for Jax.
These can be unlocked and added to your moves list by performing them in either Arcade Mode or Versus Mode.
Looking for more finishing moves? Check out my complete fatality guides:
Fatalities and babalities for Mortal Kombat on PS3
Fatalities and babalities for Mortal Kombat on Xbox 360
Jax’s Fatalities & Finishing Moves
Xbox 360
Smash And Grab — Back, Forward, Forward, Back, Y when touching the opponent
Three Points! — Forward, Forward, Back, Down, A within sweeping distance
Babality — Down, Down, Down, A in jumping distance
Stage Fatality — Down, Forward, Down, X at close range
PS3
Smash And Grab — Back, Forward, Forward, Back, Triangle when touching the opponent
Three Points! — Forward, Forward, Back, Down, X within sweeping distance
Babality — Down, Down, Down, X in jumping distance
Stage Fatality — Down, Forward, Down, Square at close range
