Question

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

Answer 1

當(dāng)負(fù)數(shù)個(gè)數(shù)為偶數(shù)時(shí)，積為正數(shù)，當(dāng)負(fù)數(shù)個(gè)數(shù)為奇數(shù)時(shí)，積為負(fù)數(shù)
分析：幾個(gè)不等于0的有理數(shù)相乘，它們的積的符號(hào)有負(fù)數(shù)的個(gè)數(shù)確定．
解答：根據(jù)幾個(gè)不等于零的數(shù)相乘，積的符號(hào)由負(fù)因數(shù)的個(gè)數(shù)決定：當(dāng)負(fù)因數(shù)有奇數(shù)個(gè)數(shù)，積為負(fù)；當(dāng)負(fù)因數(shù)的個(gè)數(shù)為偶數(shù)個(gè)時(shí)，積為正．
故答案為：當(dāng)負(fù)數(shù)個(gè)數(shù)為偶數(shù)時(shí)，積為正數(shù)，當(dāng)負(fù)數(shù)個(gè)數(shù)為奇數(shù)時(shí)，積為負(fù)數(shù)
點(diǎn)評(píng)：本題考查了有理數(shù)的乘法，幾個(gè)不等于零的數(shù)相乘，積的符號(hào)由負(fù)因數(shù)的個(gè)數(shù)決定：當(dāng)負(fù)因數(shù)有奇數(shù)個(gè)數(shù)，積為負(fù)；當(dāng)負(fù)因數(shù)的個(gè)數(shù)為偶數(shù)個(gè)時(shí)，積為正．