changing variables values !!

Hello guys , i want to ask how i can change more than value in the same time .

function IncreaseSpeed(){
if(MissionDone){
forwardSpeed +=2 ;
backwardSpeed +=2;
sidestepSpeed +=2 ;
}
}

var SpeedArrValues : int;

function Start()
{
  // add forward speed , back speed , sidestepspeed to SpeedArrValues array.
}

function IncreaseSpeed()
{
  for( var i : int =0 ; i < SpeedArrValues.length ; i++)
  {
    SpeedArrValues *+= 2;*

print(“Contents”+SpeedArrValues*);*

}
}