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

Toán Lớp 8: 2x^3-18x=0 giúp em dới=))quên ngang goyy

Toán Lớp 8: 2x^3-18x=0
giúp em dới=))quên ngang goyy

Comments ( 2 )

  1. 2x^3-18x=0
    2x.(x²-9)=0
    2x.(x²-3²)=0
    2x.(x+3).(x-3)=0
    ⇔2x.=0 hoặc (x+3)=0.hoặc(x-3)=0
    ⇒x=0,x=-3,x=3
     

  2. Answer
    2x^{3} – 18x = 0
    => 2x . (x^{2} – 9) = 0
    => $\left[\begin{matrix} 2x = 0\\ x^2 – 9 = 0\end{matrix}\right.$
    => $\left[\begin{matrix} x = 0 : 2\\ x^2 = 0 + 9\end{matrix}\right.$
    => $\left[\begin{matrix} x = 0\\ x^2 = 9\end{matrix}\right.$
    => $\left[\begin{matrix} x = 0\\ x^2 = (\pm 3)^2\end{matrix}\right.$
    => $\left[\begin{matrix} x = 0\\ x = \pm 3\end{matrix}\right.$
    $\text{Vậy}$ x \in {0 ; 3 ; -3}

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