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

Toán Lớp 8: $\frac{2+x}{2-x}$ +$\frac{4x^2}{4-x^2}$ +$\frac{x-2}{2+x}$

Toán Lớp 8: $\frac{2+x}{2-x}$ +$\frac{4x^2}{4-x^2}$ +$\frac{x-2}{2+x}$

Comments ( 2 )

  1. Giải đáp:
    = {4x}/{2 – x}
    Lời giải và giải thích chi tiết:
     {2 + x}/{2 – x} + {4x^2}/{4 – x^2} + {x – 2}/{2 + x}
    = {(2 + x)(2 + x)}/{(2 – x)(2 + x)} + {4x^2}/{2^2 – x^2} + {(x – 2)(2 – x)}/{(2 + x)(2 – x)}
    = {4 + 4x + x^2}/{(2 – x)(2 + x)} + {4x^2}/{(2 – x)(2 + x)} + {- x^2 + 4x – 4}/{(2 + x)(2 – x)}
    = {4 + 4x + x^2 + 4x^2 – x^2 + 4x – 4}/{(2 + x)(2 – x)}
    = {(x^2 – x^2 + 4x^2) + (4 – 4) + (4x + 4x)}/{(2 + x)(2 – x)}
    = {4x^2 + 8x}/{(2 + x)(2 – x)}
    = {4x(x + 2)}/{(2 + x)(2 – x)}
    = {4x}/{2 – x}
    #SunHee

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