作业帮为什么(1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0?1998×(1/11-1/2009)+11×(1/1998-1/2009)-2009×(1/11+1/1998)+3 (1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0这是怎么转换的?解释一下,前面根本减不了,急!
来源：学生作业帮助网 编辑：作业帮 时间：2024/11/17 02:53:16
为什么(1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0?1998×(1/11-1/2009)+11×(1/1998-1/2009)-2009×(1/11+1/1998)+3 (1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0这是怎么转换的?解释一下,前面根本减不了,急!
为什么(1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0?
1998×(1/11-1/2009)+11×(1/1998-1/2009)-2009×(1/11+1/1998)+3 (1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0这是怎么转换的?解释一下,前面根本减不了,急!
为什么(1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0?1998×(1/11-1/2009)+11×(1/1998-1/2009)-2009×(1/11+1/1998)+3 (1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3=3-1-1-1=0这是怎么转换的?解释一下,前面根本减不了,急!
1998×(1/11-1/2009)+11×(1/1998-1/2009)-2009×(1/11+1/1998)+3
=1998/11-1998/2009+11/1998-11/2009-2009/11-2009/1998+3（把3挪到最前面）
=3+（1998/11-2009/11）+(11/1998-2009/1998)-(1998/2009+11/2009)
=3-11/11-1998/1998-2009/2009
=3-1-1-1
=0
(1998-2009)/11-(1998+11)/2009+(11-2009）/1998+3
=-11/11-2009/2009+（-1998/1998）+3
=-1-1-1+3
=0