Question

幾個不等于0的有理數(shù)相乘，它們的積的符號如何確定________．

Answer 1

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．