合并同类项:(m+3m+5m+…+2009m)-(2m+4m+6m+…+2008m)
问题描述:
合并同类项:(m+3m+5m+…+2009m)-(2m+4m+6m+…+2008m)
答
(m+3m+5m+…+2009m)-(2m+4m+6m+…+2008m)
=m+3m+5m+…+2009m-2m-4m-6m-…-2008m
=m+(3m-2m)+(5m-4m)+…+(2009m-2008m)
=m+m+m+…+m
=m+
m2008 2
=1005m.