chứng tỏ 8 mũ 7 – 2 mũ 18 chi hết cho 14

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chứng tỏ
8 mũ 7 – 2 mũ 18 chi hết cho 14

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Khoii Minh 1 year 2020-10-31T09:28:13+00:00 2 Answers 87 views 0

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    0
    2020-10-31T09:29:39+00:00

    `8^7-2^18`

    `=2^21-2^18`

    `=2^17(2^4-2)`

    `=2^17(16-2)`

    `=2^17. 14` chia hết cho `14`

     

    0
    2020-10-31T09:30:04+00:00

    Ta có: `8^7-2^18`

    `= (2^3)^7-2^18`

    `= 2^21-2^18`

    `= 2^18.  2^3-2^18`

    `= 2^18(2^3-1)`

    `= 2^18  .7`

    `= 2^17.  2. 7`

    `= 2^17.  14`

    `=> đpcm`

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