问题 填空题 已知5m=12,5n=3,则5m-2n=______,52m+n=______. 答案 ∵5m=12,5n=3,∴5m-2n=5m÷(5n)2,=12÷32,=118;52m+n=(5m)2×5n,=14×3,=34.