which are 7 times as much as the sum of its two didits.是神马意思

学习时间:2026-04-08 23:27:34 阅读：5380

which are 7 times as much as the sum of its two didits.是神马意思啊?

满意的大叔

2026-04-08 23:27:34

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是不是这个意思：一个两位数,它的值等于自身两位数字之和的7倍。这是什么数?设十位数为x,个位数为y。(x + y)*7 = x*10 + y => x = 2y答案有：21,42,63,84