-5×(-8又7/9)-(-7)×(+79/9)+12÷(-9/79)
=-5×(-79/9)-(7)×(-79/9)+12×(-79/9)
=(-5-7+12)×(-79/9)
=0×(-79/9)
=0(-7)×(+79/9)为什么可以交换符号?负乘正得负数,正乘负也是负数。所以交换了它们的符号,但积仍不变。
-5×(-8又7/9)-(-7)×(+79/9)+12÷-(-9/79)
-5×(-8又7/9)-(-7)×(+79/9)+12÷-(-9/79)
-5×(-8又7/9)-(-7)×(+79/9)+12÷(-9/79)
-5×(-8又7/9)-(-7)×(+79/9)+12÷(-9/79)
数学人气:732 ℃时间:2020-04-14 01:32:39
优质解答
我来回答
类似推荐