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

Toán Lớp 6: so sánh hai số x và y biết :x= $2021^{2021}$-$2021^{2020; y=$2021^{2019}$ }$-$2021^{2018}$

Toán Lớp 6: so sánh hai số x và y biết :x= $2021^{2021}$-$2021^{2020; y=$2021^{2019}$ }$-$2021^{2018}$

Comments ( 2 )

  1. Lời giải và giải thích chi tiết:
    X=2021^2021-2021^2020
    =2021^2020 . 2021 – 2021 ^2020
    =2021^2020 . (2021-1)
    =2021^2020 . 2020
    $\\$
    Y=2021^2019-2021^2018
    =2021^2018 . 2021-2021^2018
    =2021^2018 . (2021-1)
    =2021^2018 . 2020
    Do 2021^2018 . 2020 < 2021^2020 . 2020
    Hay Y<X
    Vậy Y<X

  2. text(Ta có 🙂
    2021^2021 – 2021^2020
    = 2021^2020 . 2021 – 2021^2020 . 1
    = 2021^2020(2021 – 1)
    2021^2019 – 2021^2018
    = 2021^2018 . 2021 – 2021^2018 . 1
    = 2021^2018(2021 – 1)
    Vì  2021^2020 > 2021^2018
    ⇒ 2021^2020(2021 – 1) > 2021^2018(2021 – 1)
    ⇒ x > y

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