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

Toán Lớp 8: Tìm x (2x-3)(x+1)=(2x-3)(3x+5)

Toán Lớp 8: Tìm x
(2x-3)(x+1)=(2x-3)(3x+5)

Comments ( 2 )

  1. (2x-3)(x+1)=(2x-3)(3x+5)
    ⇔(2x-3)(x+1)-(2x-3)(3x+5)=0
    ⇔(2x-3)(x+1-3x-5)=0
    ⇔(2x-3)(-2x-4)=0
    ⇔2x-3=0⇔2x=3⇔x=3/2
    -2x-4=0⇔-2x=4⇔x=-2
    Vậy x={3/2,-2}
     

  2. Lời giải:
    (2x-3)(x+1)=(2x-3)(3x+5)
    ⇔(2x-3)(x+1)-(2x-3)(3x+5)=0
    ⇔(2x-3)(x+1-3x-5)=0
    ⇔(2x-3)(-2x-4)=0
    $⇔\left[\begin{matrix}2x-3=0\\ -2x-4=0\end{matrix}\right.$
    $⇔\left[\begin{matrix}2x=3\\ -2x=4\end{matrix}\right.$
    $⇔\left[\begin{matrix}x=\dfrac{3}{2}\\ x=-2\end{matrix}\right.$
    Vậy x=3/2 hoặc x=-2

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