Đáp án+Giải thích các bước giải:
`2) (x+4)/2000+(x+3)/2001=(x+2)/2002+(x+1)/2003`
`=>(x+4)/2000+1+(x+3)/2001+1=(x+2)/2002+1+(x+1)/2003+1`
`=>(x+4+2000)/2000+(x+3+2001)/2001=(x+2+2002)/2002+(x+1+2003)/2003`
`=>(x+2004)/2000+(x+2004)/2001-(x+2004)/2002-(x+2004)/2003=0`
`=>(x+2004)(1/2000+1/2001-1/2002-1/2003)=0`
Vì `1/2000+1/2001-1/2002-1/2003ne0`
`=>x+2004=0`
`=>x=-2004`
Vậy `x=-2004`
