a, x+2/x-2+1/x=-8/2x-x^2 b, 3x+1/6-x-3/2+2x-1/3+5 2 CÂU 20 Đ + VOTE + CTLHN TKS

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1. a,x+2/x-2+1/x=-8/2x-x^2  (đkxđ x khác 0, x khác 2)

   ⇔x+2/x-2+1/x=-8/x(2-x)

   ⇔x(x+2)/x(x-2)+x-2/x(x-2)=8/x(x-2)

   ⇒x^2+2x+x-2=8

   ⇔x^2+3x-10=0

   ⇔(x^2-2x)+(5x-10)=0

   ⇔x(x-2)+5(x-2)=0

   ⇔(x-2)(x+5)=0

   ⇔x=2∉đkxđ

       x=-5∈đkxđ

    vậy S={-5}

    

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