(x-2)*60/x 怎么变成60-120/X
问题描述:
(x-2)*60/x 怎么变成60-120/X
答
[(x-2)*60]/x
=(60x-120)/x
=(60x)/x-120/x
=60-120/x看不懂啊啊 啊啊= =。~!!!