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( 3 +|+ 6 +|+ 9 +|+ .... +|+ 369 ) + ( 2 +|+ 4 +|+ 6 +|+ .... +|+ 246 ) =?

Răspuns :

3+6+9+....+369 = 3(1+2+3+...+123)
2+4+6+....+246 = 2(1+2+3+...+123)

3(1+2+3+...+123) + 2(1+2+3+...+123) =
5(1+2+3+...+123) =
5*123*124:2 =
5*123*62 = 38130