Question

X+(X+1)+(x+2)+++++++(x+2009)=2009.2010

 

Answer 1

X+(X+1)+(x+2)+++++++(x+2009)=2009.2010

=>2010.X+(1+2+3+...........+2009)=2009.2010

1+2+3+...........+2009 có 2009 số hạng

=>2010.X+[(2009+1).2009:2]=2009.2010

2010.X+(2010.2009:2)=2009.2010

2010.X=2009.2010-(2009.2010:2)=2010.2009:2

=>X=2009:2=1004,5

Vậy X=1004,5

Answer 2

x+(x+1)+(x+2)..........(x+2009)=4038090

=>x.(2009+1)=4038090.

x.2010=4038090.

x=4038090:10.

x=2009.

Nhớ-k-cho-mình-nhé!Chúc-bạn-học-tốt.