Maximum point?

Ok another question, how do you set the maximum point of an x value?

I tried
var X = MC.x
Math.max(x = 100)

but that didnt seem to work…

McBtnDrag.x = 0;

function init()
{
var X = McBtnDrag.x
Math.max(X = 300)
X = 299
trace(“hello”)
}
init();

McBtnDrag.x = 0;

function init()
{
var X = McBtnDrag.x
Math.max(X = 300)
X = 299
trace(“hello”)
}
init();

does not work at all :\

oh wait, Math.Max is something else. Its obvious why that doesnt work