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

Toán Lớp 6: Cho A= 1+2¹+2² +…+2¹⁰⁰+2¹⁰¹.Chứng minh A⁝7

Toán Lớp 6: Cho A= 1+2¹+2² +…+2¹⁰⁰+2¹⁰¹.Chứng minh A⁝7

Comments ( 2 )

  1. Lời giải chi tiết:
    Ta có:
    A=1+2^1+2^2+…+2^100+2^101
    A=(1+2^1+2^2)+(2^3+2^4+2^5)+…+(2^99+2^100+2^101)
    A=1.(1+2+2^2)+2^3(1+2+2^2)+…+2^99(1+2+2^2)
    A=1.7+2^(3).7+…+2^(99).7
    A=7.(1+2^3+…+2^99)\vdots7
    Vậy A\vdots7

  2. A= 1+2¹+2² +…+2¹⁰⁰+2¹⁰¹
    A=(1+2¹+2²)+…+(2^99+2¹⁰⁰+2¹⁰¹)
    A=7+….+2^99.(1+2¹+2²)
    A=7+…+2^99.7
    A=7.(1+…+2^99)
    ⇒A⁝7
     

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

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