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

Toán Lớp 9: Giúp mik vs √2021-√(√2020-√2021)^2

Toán Lớp 9: Giúp mik vs √2021-√(√2020-√2021)^2

Comments ( 2 )

  1. $\sqrt{2021}-\sqrt{(\sqrt{2020}-\sqrt{2021})²}$
    $\sqrt{2021}-|\sqrt{2020}-\sqrt{2021}|$
    $=\sqrt{2021}-\sqrt{2021}+\sqrt{2020}$
    $=\sqrt{2020}$

  2. \sqrt{2021} – \sqrt{(\sqrt{2020} – \sqrt{2021})^2}
    = \sqrt{2021} – |\sqrt{2020} – \sqrt{2021}|
    Do  2021 > 2020
    ⇒ \sqrt{2021} > \sqrt{2020}
    ⇒ \sqrt{2021} – (\sqrt{2021} – \sqrt{2020})
    (Do  \sqrt{2020} – \sqrt{2021} < 0)
    ⇒ \sqrt{2021} – \sqrt{2021} + \sqrt{2020}
    = \sqrt{2020}

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