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222-9+11+12:2*14+14 = ? ( )

Toán Lớp 9: Chứng minh : `(11^10 -1) \vdots 100`

Toán Lớp 9: Chứng minh : (11^10 -1) \vdots 100

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    $11^{10}-1\\=(11^5)^2-1\\=(11^5-1)(11^5+1)\\=(11-1)(11^4+11^3+11^2+11+1)(11+1)(11^4-11^3+11^2-11+1)\\=10.12.(11^14+11^3+11^2+11+1)(11^4-11^3+11^2-11+1)$
    Vì $11^4+11^3+11^2+11+1=\overline{…1}+\overline{….1}+\overline{…..1}+\overline{….1}+\overline{….1}=\overline{….5}\vdots 5$
    Mà $12\vdots 2$
    $10\vdots 10$
    $\to 10.12.(11^4+11^3+11^2+11+1)\vdots 100$
    $\to 10.12.(11^4+11^3+11^2+11+1)(11^4-11^3+11^2-11+1)\vdots 100$
    $Hay\,11^{10}-1\vdots 100$

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222-9+11+12:2*14+14 = ? ( )

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