(2-x)/2001-1=(1-x)/2002-x/2003

2−x2001−1=1−x2002−x2003⇔2−x2001+1=1−x2002+1−x2003+1⇔2−x+20012001=1−x+20022002+2003−x2003⇔2003−x12001−12002−12003=0⇔2003−x=0⇔x=2003