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

Toán Lớp 7: Tìm x bt: (2x-1)^2=(2x-1)^4

Tháng Chín 19, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: Tìm x bt: (2x-1)^2=(2x-1)^4

Comments ( 2 )

  1. aivilanlan
    aivilanlan
    19 Tháng Chín, 2022 at 2:18 sáng
    Reply
    (2x – 1)^2 = (2x – 1)^4
    =>(2x – 1)^2 – (2x – 1)^4 = 0
    (2x – 1)^2 . 1 – ( 2x – 1)^2 . (2x – 1)^2 = 0
    (2x – 1)^2 . [ 1 – (2x – 1)^2] = 0
    =>+) Trường hợp 1 :
    (2x – 1)^2 = 0
    => 2x – 1 = 0
    2x = 0 + 1
    2x = 1
    x = 1 : 2
    x = 1/2
    +) Trường hợp 2 :
    1 – ( 2x – 1)^2 = 0
    (2x – 1)^2 = 1 – 0
    (2x – 1)^2 = 1
    (2x – 1)^2 = (+-1)^2
    => \(\left[ \begin{array}{l}2x-1=1\\2x-1=-1\end{array} \right.\) 
    => \(\left[ \begin{array}{l}2x=1+1\\2x=-1+1\end{array} \right.\) 
    => \(\left[ \begin{array}{l}2x=2\\2x=0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=2: 2\\x=0 : 2\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=1\\x=0\end{array} \right.\) 
    Vậy x \in { 1/2 ; 1 ; 0}
    #caty09

  2. hienchaudiem
    hienchaudiem
    19 Tháng Chín, 2022 at 2:17 sáng
    Reply
    Giải đáp+Lời giải và giải thích chi tiết:
    (2x-1)^2=(2x-1)^4
    <=>(2x-1)^4-(2x-1)^2=0
    <=>(2x-1)^2[(2x-1)^2-1]=0
    <=>(2x-1)^2(2x-1-1)(2x-1+1)=0
    <=>2x(2x-1)^2(2x-2)=0
    <=>[(2x=0),((2x-1)^2=0),(2x=2):}
    <=>[(x=0),(x=1/2),(x=1):}
    Vậy x\in{0;1/2;1} 

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

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