\(\frac{x+1}{2004}+\frac{x+2}{2003}=\frac{x+3}{2002}+\frac{x+4}{2001}\\
\)
Cộng từng hạng tử của hai vế với 1
\(\frac{x+1}{2004}+1+\frac{x+2}{2003}+1=\frac{x+3}{2002}+1+\frac{x+4}{2001}+1\)
\(\Rightarrow\frac{x+1+2004}{2004}+\frac{x+2+2003}{2003}=\frac{x+3+2002}{2002}+\frac{x+4+2001}{2001}\)
\(\Rightarrow\frac{x+2005}{2004}+\frac{x+2005}{2003}-\frac{x+2005}{2002}-\frac{x+2005}{2002}=0\)
\(\Rightarrow\left(x+2005\right)\left(\frac{1}{2004}+\frac{1}{2003}-\frac{1}{2002}-\frac{1}{2001}\right)=0\)
Vì \(\left(\frac{1}{2004}+\frac{1}{2003}-\frac{1}{2002}-\frac{1}{2001}\right)\ne0\)nên \(x+2005=0\Rightarrow x=-2005\)
Phương trình có nghiệm duy nhất: x=2005
(x+1)/2004+(x+2)/2003=(x+3)/2002+(x+4)/2001
(x+1)/2004+1 +(x+2)/2003 +1=(x+3)/2002+1 (x+4)/2001+1
=> x+2005/2004+(x+2005)/2003-(x+2005)/2002-(x+2005)/2002=0
(x+2005)(1/2004+1/2003-1/2002-1/2001)=0
=>x+2005=0
=>x=-2005
