计算x-2x+3x-4x+...-2008x+2009x

分类: 作业答案 • 2021-12-19 11:39:02

问题描述：

答

x-2x+3x-4x+...-2008x+2009x
=x(1-2+3-4+...-2008+2009)
=x(-1-1-1-...-1+2009)
=x(-1*1004+2009)
=x(2009-1004)
=1005x

答

x-2x+3x-4x+...-2008x+2009x
= (x-2x)+(3x-4x)+...+(2007x-2008x)+2009x
= -1004x+2009x
= 1005x