Doors and Windows - Hanging a pre-hung door

I have purchased pine pre-hung doors. I don't think I will have any trouble installing them but the closet door is in question. The cement floor (in the basement) is un level so when I place the pre-hung door in the opening the jamb rests on the cement on one side of the door and is about an inch higher than level on the other jamb. Will work fine as far as I am concerned but won't you see the gap between the door jamb and the carpet (after it has been installed) on the side of the door jamb where the floor is not level? Another question, do you have to put a shim under the door jambs when placing on top of cement floors? :mask:

Regarding the out of level floor, one inch is a lot of drop in a doorway! If you haven't already, set the level in the doorway and determine the exact drop on the opposite side. If it really is an inch, what I would probably do is cut 1/2" off the bottom of the long jamb, and shim the other side up 1/2", making sure the shim is 100% concealed under the door jamb. Once the carpet is installed, you'll be able to determine how much, if any, to cut off the bottom of the door so that it doesn't drag on the carpet.

I don't usually shim up doors on cement, it all depends on what kind of flooring is going down. You might consider some sort of self-leveling cement in that area, if you can take some of that slope out by using it, now is probably the time to do it.