you can make an object move from a current location (x,y) to target location (tx,ty) by doing something like this :
Did you even read the question? He's not asking for linear movement, he's asking for A* pathfinding
, completely different from what you posted. Not to mention that he's not even using vectors like in your example (minus/negative sign doesn't operate on vector objects).
I don't use Slick, but here's some explanation and example
code by kevglass (you've probably seen it already, oh well).