Question

Chung minh rang abcabc chia het cho 7, 11, 13 va abc

Answer 1

abcabc = abc x 1001 = abc x 7 x 11 x 13

Vậy abcabc cha hết cho ab ; 7;13;11  

Answer 2

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Answer 3

abcabc = abc.1000 + abc = abc ( 1000 + 1 )

                                      = abc . 1001

                                      = abc . 7 . 11 .13

=> abcabc chia hết cho 7, 13, 11, abc ( đpcm )

Answer 4

abcabc = a.100000 +b 10000+c . 1000+a.100+b . 10 +c

= 100100a + 10010 b + 1001 c

100100a chia het cho 11 ; 13

10010b chia het cho 11;13

1001c chia het cho 11 ; 13

=> abcabc chia het cho abcabc