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

Toán Lớp 8: thực hiện phép tính x+3/x+2+4+x/2-x

Toán Lớp 8: thực hiện phép tính x+3/x+2+4+x/2-x

Comments ( 2 )

  1. $\dfrac{x+3}{x+2}$ + $\dfrac{4+x}{2-x}$ ( ĐKXĐ : x \ne ± 2 )
    = $\dfrac{x+3}{x+2}$ + $\dfrac{-(4+x)}{x-2}$
    = $\dfrac{x+3}{x+2}$ + $\dfrac{-4 – x}{x-2}$
    MTC: (x+2)(x-2)
    = $\dfrac{(x-2)(x+3)}{(x+2)(x-2)}$ +$\dfrac{(-4-x)(x+2)}{(x+2)(x-2)}$
    = $\dfrac{x² – 2x + 3x  – 6 + (-4x) – 8 – x² – 2x }{(x+2)(x-2)}$
    =$\dfrac{-5x – 14}{(x+2)(x-2)}$

  2. Giải đáp+Lời giải và giải thích chi tiết:
    (x+3)/(x+2)+(4+x)/(2-x)
    =(x+3)/(x+2)-(4+x)/(x-2)
    =[(x+3)(x-2)]/[(x+2)(x-2)]-[(4+x)(x+2)]/[(x+2)(x-2)]
    =[x(x-2)+3(x-2)]/[(x+2)(x-2)]-[4(x+2)+x(x+2)]/[(x+2)(x-2)]
    =(x^2-2x+3x-6)/[(x+2)(x-2)]-(4x+8+x^2+2x)/[(x+2)(x-2)]
    =(x^2-2x+3x-6-4x-8-x^2-2x)/[(x+2)(x-2)]
    =(-5x-14)/[(x+2)(x-2)]
     

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

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