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

Toán Lớp 8: Tìm x : a) x^3-x/x^2-2x+1 = 0 b)(2x-5)^2+(y-3)^2=0

Toán Lớp 8: Tìm x :
a) x^3-x/x^2-2x+1 = 0
b)(2x-5)^2+(y-3)^2=0

Comments ( 1 )

  1. Giải đáp:
    a) $x=0$ hoặc $x=-1$
    b) $x=\dfrac{5}{2};y=3$
    Lời giải và giải thích chi tiết:
    a)
    $\dfrac{x^3-x}{x^2-2x+1}=0\,\,\,(x\ne1)\\⇔\dfrac{x(x^2-1)}{(x-1)^2}=0\\⇔\dfrac{x(x-1)(x+1)}{(x-1)^2}=0\\⇔\dfrac{x(x+1)}{x-1}=0\\\to x(x+1)=0\\⇔\left[\begin{array}{l}x=0\\x=-1\end{array}\right.$ (thoả mãn)
    Vậy $x=0$ hoặc $x=-1$
    b)
    $(2x-5)^2+(y-3)^2=0$
    Ta có: $(2x-5)^2\ge0\,\,\,\forall x, (y-3)^2\ge0\,\,\,\forall y$
    $\to (2x-5)^2+(y-3)^2=0⇔\begin{cases}(2x-5)^2=0\\(y-3)^2=0\end{cases}\\⇔\begin{cases}x=\dfrac{5}{2}\\y=3\end{cases}$
    Vậy $x=\dfrac{5}{2};y=3$

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

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