幾個不等于0的有理數(shù)相乘,它們的積的符號如何確定________.
當負數(shù)個數(shù)為偶數(shù)時,積為正數(shù),當負數(shù)個數(shù)為奇數(shù)時,積為負數(shù)
分析:幾個不等于0的有理數(shù)相乘,它們的積的符號有負數(shù)的個數(shù)確定.
解答:根據(jù)幾個不等于零的數(shù)相乘,積的符號由負因數(shù)的個數(shù)決定:當負因數(shù)有奇數(shù)個數(shù),積為負;當負因數(shù)的個數(shù)為偶數(shù)個時,積為正.
故答案為:當負數(shù)個數(shù)為偶數(shù)時,積為正數(shù),當負數(shù)個數(shù)為奇數(shù)時,積為負數(shù)
點評:本題考查了有理數(shù)的乘法,幾個不等于零的數(shù)相乘,積的符號由負因數(shù)的個數(shù)決定:當負因數(shù)有奇數(shù)個數(shù),積為負;當負因數(shù)的個數(shù)為偶數(shù)個時,積為正.