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

Toán Lớp 8: giải phương trình $\frac{x-1}{x+2}$ $-$ $\frac{x+1}{2-x}$ $=$ $\frac{2(x^{2}+2)}{x^{2}-4}$

Toán Lớp 8: giải phương trình
$\frac{x-1}{x+2}$ $-$ $\frac{x+1}{2-x}$ $=$ $\frac{2(x^{2}+2)}{x^{2}-4}$

Comments ( 2 )

  1. Giải đáp+Lời giải và giải thích chi tiết:
    (x-1)/(x+2)-(x+1)/(2-x)=(2(x²+2))/(2(x²+2))/(x²-4)
    =>((x-1)(x-2)+(x+1)(x+2))/((x-2)(x+2))=(2x²+4)/((x-2)(x+2))
    =>(x²-2x-x+2+x²+2x+x+2-2x²-4)/((x-2)(x+2))=0
    =>0/((x-2)(x+2))=0
    =>0=0
    Vậy S={0}
     
     

  2. $\dfrac{x-1}{x+2}-\dfrac{x+1}{2-x}=\dfrac{2(x^2+2)}{x^2-4}$
    $⇔ \dfrac{(x-2)(x-1)}{(x-2)(x+2)}+\dfrac{x+1}{x-2}=\dfrac{2x^2+4}{(x-2)(x+2)}$
    $⇔ \dfrac{x^2-x-2x+2}{(x-2)(x+2)}+\dfrac{x^2-2x+x-2}{(x-2)(x+2)}=\dfrac{2x^2+4}{(x-2)(x+2)}$
    $⇔ \dfrac{x^2-3x+2}{(x-2)(x+2)}+\dfrac{x^2-x-2}{(x-2)(x+2)}=\dfrac{2x^2+4}{(x-2)(x+2)}$
    $⇔ \dfrac{x^2-3x+2+x^2-x-2}{(x-2)(x+2)}=\dfrac{2x^2+4}{(x-2)(x+2)}$
    $⇔ \dfrac{2x^2-4x}{(x-2)(x+2)}=\dfrac{2x^2+4}{(x-2)(x+2)}$
    $⇔ \dfrac{2x^2-4x}{(x-2)(x+2)}-\dfrac{2x^2+4}{(x-2)(x+2)}=0$
    $⇔0=0$
    $#thanhmaii2008$

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

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