Ta có
\(\dfrac{x-3}{2008}=\dfrac{x+1}{2009}\Rightarrow2009\left(x-3\right)=2008\left(x+1\right)\)
\(\Rightarrow2009x-2009.3=2008x+2008\)
\(\Rightarrow2009x-2008x=2009.3+2008\)
\(\Rightarrow x=8035\)
Mà \(x-y=4009\)
\(\Rightarrow8035-y=4009\)
\(\Rightarrow y=4026\)