Easing a slider with on(release)

Here goes… I’ve been working on this for a good while now and I can’t FULLY get it to work, so I need some help…

I have a slider that controls my audio volume, it works great… I also have stop and play buttons that (you guessed it) stop and play the audio… Now the effect that I’m going for is when you click the stop button the slider gracefully slides back to “zero” (which in my case it would be something like _x = -50) and when you hit the play button the slider would smoothly slide all the way to the right side of the slider (which would be _x = 50)…

I’ve gotten it to work to the point where when you click on the buttons they go to the right place but I’m having trouble easing them there… did that make sense?