3楼良辰美景
(高瞻远瞩)
发表于 2008-6-24 13:47
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11112^2+11112*11111+11111^2 , a=11111,b=11112
=a^2+b^2+ab
=a^2+ab+b^2+ab-ab
=a(a+b)+b(a+b)-ab
=(a+b)^2-ab
=(a+b)^2-a(a+1)
=(a+b)^2-a^2-a
=(2a+b)b-a
=(3a+1)b-a
=3ab+(b-a)
=3ab+1
=3*11111*11112+1
=33333*11112+1.