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

Toán Lớp 8: ( 3x-1)tất cả mũ 2 -9=0 Giải nhanh hộ em với ạ

Toán Lớp 8: ( 3x-1)tất cả mũ 2 -9=0
Giải nhanh hộ em với ạ

Comments ( 2 )

  1. (3x-1)^2-9=0
    ⇔(3x-1-3)(3x-1+3)=0
    ⇔(3x-4)(3x+2)=0
    ⇔3x-4=0 hoặc 3x+2=0
    ⇔x=4/3 hoặc x=-2/3
    Vậy S={4/3;-2/3}
     

  2. (3x-1)^2-9=0
    <=>(3x-1)^2-3^2=0
    <=>(3x-1-3)(3x-1+3)=0
    <=>(3x-4)(3x+2)=0
    <=> \(\left[ \begin{array}{l}3x-4=0\\3x+2=0\end{array} \right.\)
    <=> \(\left[ \begin{array}{l}3x=4\\3x=-2\end{array} \right.\)
    <=> \(\left[ \begin{array}{l}x=\frac{4}{3}\\x=\frac{-2}{3}\end{array} \right.\) 
    vậy S={4/3;-2/3} 
     

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