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

Toán Lớp 7: tìm x biết: (3x -1)^6=(3x-1)^4 nhanh giúp em ạ

Tháng Bảy 30, 2022 Toán học 2 Comments 0 views

Toán Lớp 7: tìm x biết: (3x -1)^6=(3x-1)^4 nhanh giúp em ạ

Comments ( 2 )

  1. phuongthaongoc
    phuongthaongoc
    30 Tháng Bảy, 2022 at 3:12 chiều
    Reply
    (3x-1)^6 = (3x-1)^4
    => (3x-1)^6 – (3x-1)^4 =0
    => (3x-1)^4 [(3x-1)^2 – 1] =0
    +) (3x-1)^4 =0
    => 3x-1=0
    => 3x =1
    => x= 1/3
    +) (3x-1)^2 -1=0
    => (3x-1)^2 =1
    => \(\left[ \begin{array}{l}(3x-1)^2=1^2\\(3x-1)^2=(-1)^2\end{array} \right.\) 
    => \(\left[ \begin{array}{l}3x-1=1\\3x-1=-1\end{array} \right.\) 
    => \(\left[ \begin{array}{l}3x =2\\3x=0\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x=\frac{2}{3}\\x=0\end{array} \right.\) 
    Vậy x in{1/3 ; 2/3 ;0}

  2. mocmien87
    mocmien87
    30 Tháng Bảy, 2022 at 3:11 chiều
    Reply
    Giải đáp:
    x=1/3; x=2/3; x=0
    Lời giải và giải thích chi tiết:
    (3x-1)^6=(3x-1)^4
    ⇒(3x-1)^6-(3x-1)^4=0
    ⇒(3x-1)^4*[(3x-1)^2-1]=0
    ⇒\(\left[ \begin{array}{l}3x-1=0\\(3x-1)^2-1=0\end{array} \right.\)
    ⇒\(\left[ \begin{array}{l}3x=1\\(3x-1)^2=1\end{array} \right.\) ⇒\(\left[ \begin{array}{l}x=\dfrac{1}{3}\\3x-1=1\\3x-1=-1\end{array} \right.\) ⇒\(\left[ \begin{array}{l}x=\dfrac{1}{3}\\3x=2\\3x=0\end{array} \right.\) ⇒\(\left[ \begin{array}{l}x=\dfrac{1}{3}\\x=\dfrac{2}{3}\\x=0\end{array} \right.\) 
    Vậy x=1/3; x=2/3; x=0

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

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