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

Toán Lớp 8: giúp mik vs ạ a)2022^2-2021^2 b)45^2+40^2-15^2+80.45 c)2021^2-4042.2020+2020^2

Toán Lớp 8: giúp mik vs ạ
a)2022^2-2021^2
b)45^2+40^2-15^2+80.45
c)2021^2-4042.2020+2020^2

Comments ( 2 )

  1. Giải đáp + Lời giải và giải thích chi tiết:
     a, 2022^2 – 2021^2
    = (2022 – 2021)(2022 + 2021)
    = 1 . 4043
    = 4043
    b, 45^2 + 40^2 – 15^2 + 80 . 45
    = (45^2 + 2 . 40 . 45 + 40^2) – 15^2
    = (45 + 40)^2 – 15^2
    = 85^2 – 15^2
    = (85 – 15)(85 + 15)
    = 70 . 100 = 7000
    c, 2021^2 – 4042 . 2020 + 2020^2
    = 2021^2 – 2 . 2021 . 2020 + 2020^2
    = (2021 – 2020)^2
    = 1^2 = 1
     

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

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