Xiao Ming's father is 5 years older than his mother. If the ages of father and mother will be an integer multiple of Xiao Ming's age in three years, then how many years ago, the ages of father and mother will also be exactly integer multiples of Xiao Ming's age.
小明的爸爸比妈妈大5岁．如果3年后爸爸和妈妈的年龄都将是小明年龄的整数倍，那么，在多少年前爸爸和妈妈的年龄也都正好是小明年龄的整数倍．
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