Moving a MC?

I have a small question. I made a MC and a button. I want that when i press the button the MC moves by so and so many x and y… I made the button like

on (release) {
myMC._x=_x+150;
}

or so,but it didnt moved. I want that it slides or moves so far and not just appears 150 pixels farrer or so… :confused:

Any1 can help? :slight_smile: