To enlarge the x co-ordinates of a function f(x), you need to change the function to f(ax), where 1/a is the amount that you want to enlarge it by.

So, to multiply all the x co-ordinates in y=x:sup2 by 2, you would have to change it to y=(x/2):sup2 = x:sup2/4.

And changing y = 1/x *does* scale it in the y direction, it just happens to scale in in the x direction as well because of symmetry.