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

Toán Lớp 8: Tính: x^2+2/x^3-1+2/x^2+x+1+1/1-x

Toán Lớp 8: Tính: x^2+2/x^3-1+2/x^2+x+1+1/1-x

Comments ( 2 )

  1. \frac{x^2+2}{x^3-1} + \frac{2}{x^2+x+1} + \frac{1}{1-x}              ( x \ne 1 )
    = \frac{x^2+2}{(x-1)(x^2+x+1)} +  \frac{2}{x^2+x+1} – \frac{1}{x-1}
    = \frac{x^2+2+2 ( x – 1 ) – ( x^2 + x + 1 )}{(x-1)(x^2+x+1)}
    = \frac{x^2+2 +2x-2 -x^2-x-1}{(x-1)(x^2+x+1)}
    = \frac{x-1}{(x-1)(x^2+x+1)}
    = \frac{1}{ x^2+x+1}
     

  2. Giải đáp+Lời giải và giải thích chi tiết:
     (x^2+2)/(x^3-1)+2/(x^2+x+1)+1/(1-x) (x \ne 1)
    =(x^2+2)/[(x-1)(x^2+x+1)]+[2(x-1)]/[(x-1)(x^2+x+1)]-1/(x-1)
    =(x^2+2)/[(x-1)(x^2+x+1)]+(2x-2)/[(x-1)(x^2+x+1)]-(x^2+x+1)/[(x-1)(x^2+x+1)]
    =(x^2+2+2x-2-x^2-x-1)/[(x-1)(x^2+x+1)]
    =(x-1)/[(x-1)(x^2+x+1)]
    =1/(x^2+x+1)

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

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