The ornamental design for an X-ray machine, as shown and described.
FIG. 1 is a front perspective view of an X-ray machine showing our new design;
FIG. 2 is a right side elevational view thereof;
FIG. 3 is front elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a rear elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines adjacent to the shaded areas represent the bounds of the claim, while other broken lines are directed to the environment; the broken lines form no part of the claimed design.