2) コピー機の電源を(入れて(いれて)→ )おいてください。
It depends on the meaning of "入れる". /If "入れる" means "put on" as in this sentence, its opposite is "切る" which means "put off". /If "入れる" means "put in" as you thought, its opposite is "出す" which means "take out". /コピー機の電源を切っておいてください。