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

Toán Lớp 8: Tìm x biết a, x² – 4x + 3 = 0 b, x³ – 8x = 0 c, x(2x-5) – 2x+5 = 0 d, 3/5x(x² – 9) = 0

Tháng Chín 19, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Tìm x biết
a, x² – 4x + 3 = 0
b, x³ – 8x = 0
c, x(2x-5) – 2x+5 = 0
d, 3/5x(x² – 9) = 0

Comments ( 2 )

  1. buianhtuan
    buianhtuan
    19 Tháng Chín, 2022 at 3:12 sáng
    Reply
    Giải đáp:
     a, x² – 4x + 3 =0
        X² – x – 3x + 3 =0
        X(x-1) -3(x-1)  =0
               (x-3)(x-1) =0
       =>\(\left[ \begin{array}{l}x-3=0\\x-1=0\end{array} \right.\) =>\(\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\) 
    b, x³ – 8x =0
       x(x² – 8)=0
      X(x-√8)(x+√8)=0
    =>\(\left[ \begin{array}{l}x=0\\x+√ 8=0\\x-√ 8=0\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x=0\\x=-√ 8\\x=√ 8\end{array} \right.\) 
    c, x(2x-5) – 2x + 5 =0
       x(2x-5) – (2x – 5)=0
            (2x-5)(x-1)   =0
    =>   \(\left[ \begin{array}{l}2x-5=0\\x-1=0\end{array} \right.\)
    =>  \(\left[ \begin{array}{l}x=5/2\\x=1\end{array} \right.\) 
    d, 3/5x(x²-9) =0
       3/5x(x-3)(x+3)=0
    => \(\left[ \begin{array}{l}3/5x=0\\x-3=0\\x+3=0\end{array} \right.\) 
    => \(\left[ \begin{array}{l}x=0\\x=3\\x=-3\end{array} \right.\) 
    Lời giải và giải thích chi tiết:
     #HN

  2. huenthanh97
    huenthanh97
    19 Tháng Chín, 2022 at 3:12 sáng
    Reply
    a, x^2 – 4x + 3=0
    x^2 – x – 3x + 3=0
    x(x-1) – 3(x-1) =0
    (x-1)(x-3)=0
    =>\(\left[ \begin{array}{l}x-1=0\\x-3=0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=1\\x=3\end{array} \right.\) 
    \text{Vậy} x ∈ {1;3}
    b, x^3 – 8x =0
    x(x^2 – 8)=0
    x(x+ √8 )(x – √8 )=0
    =>\(\left[ \begin{array}{l}x=0\\x+ √8 =0\\x – √8 =0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=0\\x=- √8\\x=√8\end{array} \right.\) 
    \text{Vậy} x ∈ {0; -√8 ; √8 }
    c, x(2x-5) – 2x+5=0
    x(2x-5) -(2x-5)=0
    (2x-5)(x-1)=0
    =>\(\left[ \begin{array}{l}2x-5=0\\x-1=0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=\frac{5}{2}\\x=1\end{array} \right.\) 
    \text{Vậy} x ∈ { 5/2 ;1}
    d, 3/5 x(x^2 -9)=0
    3/5 x(x+3)(x-3)=0
    =>\(\left[ \begin{array}{l}\frac{3}{5}x=0\\x+3=0\\x-3=0\end{array} \right.\) 
    =>\(\left[ \begin{array}{l}x=0\\x=-3\\x=3\end{array} \right.\) 
    \text{Vậy} x ∈ {0;-3;3}

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

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