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

Toán Lớp 7: Cho dãy tỉ số bằng nhau a/2019 = b/2021 = c/2023 Chứng minh rằng (a-c)^2/4 = (a-b) x (b-c) giúp mk với ạ!!

Toán Lớp 7: Cho dãy tỉ số bằng nhau a/2019 = b/2021 = c/2023
Chứng minh rằng (a-c)^2/4 = (a-b) x (b-c)
giúp mk với ạ!!

Comments ( 2 )

  1. $\\$
    Đặt $\dfrac{a}{2019}=\dfrac{b}{2021}=\dfrac{c}{2023}=k(k\ne 0)$
    $\Rightarrow a=2019k , b=2021k, c=2023k$
    $\dfrac{(a-c)^2}{4}\\=\dfrac{(2019k-2023k)^2}{4}\\=\dfrac{16k^2}{4}\\=4k^2(1)\\(a-b)(b-c)\\=(2019k-2021k)(2021k – 2023k)\\=(-2k).(-2k)\\=4k^2(2)\\(1)(2)\Rightarrow đpcm$
     

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