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

Toán Lớp 8: tìm x biết 7x nhân (x+5)-2x-10=0 3x nhân x-2-x+2=0 x mũ 2 nhân(x-3)-4 nhân(x-3)

Toán Lớp 8: tìm x biết 7x nhân (x+5)-2x-10=0 3x nhân x-2-x+2=0 x mũ 2 nhân(x-3)-4 nhân(x-3)

Comments ( 1 )

  1. Lời giải và giải thích chi tiết:
    7x(x+5)-2x-10=0
    <=>7x(x+5)-2(x+5)=0
    <=>(x+5)(7x-2)=0
    <=> \(\left[ \begin{array}{l}x+5=0\\7x-2=0\end{array} \right.\)
    <=> \(\left[ \begin{array}{l}x=-5\\x=\dfrac{2}{7}\end{array} \right.\) 
    Vậy x in {-5; 2/7}
                                                 
    3x(x-2)-x+2=0
    <=>3x(x-2)-(x-2)=0
    <=>(x-2)(3x-1)=0
    <=> \(\left[ \begin{array}{l}x-2=0\\3x-1=0\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=2\\x=\dfrac{1}{3}\end{array} \right.\) 
    Vậy x in {2; 1/3}
                                                 
    x^2 (x-3)-4(x-3)=0
    <=>(x-3)(x^2 -4)=0
    <=> \(\left[ \begin{array}{l}x-3=0\\x^2-4=0\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=3\\x^2=4\end{array} \right.\) 
    <=> \(\left[ \begin{array}{l}x=3\\x=-2\\x=2\end{array} \right.\) 
    Vậy x in {-2;2;3}

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

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