[color=red]1-Three suspects are outside this room. The others are in the room.
[color=blue]2-Three suspects are out of this room. The others are in the room.
Does “1” imply that they are closeby?
Does “2” imply that they were in the room and have now left.
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Which is correct:
[color=red]3-We have found three liveable planets outside the solar system.
[color=blue]4-We have found three lievable planets out of the solar system.
Gratefully,
Navi.
not a teacher
1-Three suspects are outside this room. The others are in the room.
This sentence means that the three suspects are outside the room, probably by the door or in the hallway.
2-Three suspects are out of this room. The others are in the room.
This one means that the three suspects are out of this room - they can be anywhere; by the door, in the hallway, at home, etc.
If you want the sentence to imply that the suspects have left the room, you can change it to: “Three suspects are now out of this room.” [You have just thrown them out]. or “Three suspects left this room”
Regarding your second question, I think the first sentence sounds better, although both of them are grammatically correct.
We have found three liveable/habitable planets outside of the/our solar system.
Hope this helps!