Ta có :
2a + 2 ( a + 1) + ... + ( a + 2003 )
= 4008a + 2 ( 1 + 2 + ... + 2003 )
= 2004 ( 2a + 2003 )
= 8030028
Như vậy :
8030028 = 2004+ 2008 + .... + 6010
Ta có:
2a+2(a+1)+...+2(a+2003)=4008a+2(1+2+...+2003)=2004(2a+2003)=8030028⇒a=10022a+2(a+1)+...+2(a+2003)=4008a+2(1+2+...+2003)=2004(2a+2003)=8030028⇒a=1002
Như vậy:
8030028=2004+2008+...+60108030028=2004+2008+...+6010