Răspunsuri

2014-05-13T11:10:08+03:00
1997 + 2 x( 1+2+...+1996 )
1+2+...+1996=(1996*1997)/2

1997+2*(1996*1997)/2   - 2 cu 2 se simplifica si ramane
1997+1996*1997=
1997(1+1996)=
1997*1997 => patrat perfect
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