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

Toán Lớp 8: Tính a, x^2/x-2 + 3x/x-2 – x-4/x-2 b, 2/x^2-1 + x+1/x-1 – x-1/x+1

Toán Lớp 8: Tính
a, x^2/x-2 + 3x/x-2 – x-4/x-2
b, 2/x^2-1 + x+1/x-1 – x-1/x+1

Comments ( 2 )

  1. Giải đáp:
    a) {x^2 + 2x + 4}/{x – 2}
    b) {4x + 2}/{(x – 1)(x + 1)}
    Lời giải và giải thích chi tiết:
    a)
    {x^2}/{x – 2} + {3x}/{x – 2} – {x – 4}/{x – 2}
    = {x^2 + 3x – (x – 4)}/{x – 2}
    = {x^2 + 3x – x + 4}/{x – 2}
    = {x^2 + 2x + 4}/{x – 2}
    $\\$
    b)
    2/{x^2 – 1} + {x + 1}/{x – 1} – {x – 1}/{x + 1}
    =2/{(x – 1)(x + 1)} + {x + 1}/{x – 1} – {x – 1}/{x + 1}
    =2/{(x – 1)(x + 1)} + {(x + 1)(x + 1)}/{(x – 1)(x + 1)} – {(x – 1)(x – 1)}/{(x – 1)(x + 1)}
    = 2/{(x – 1)(x + 1)} + {x^2 + 2x + 1}/{(x – 1)(x + 1)} – {x^2 – 2x + 1}/{(x – 1)(x + 1)}
    = {2 + x^2 + 2x + 1 – (x^2 – 2x + 1)}/{(x – 1)(x + 1)}
    = {2 + x^2 + 2x + 1 – x^2 + 2x – 1}/{(x – 1)(x + 1)}
    = {(x^2 – x^2) + (2x + 2x) + (2 + 1 – 1)}/{(x – 1)(x + 1)}
    = {4x + 2}/{(x – 1)(x + 1)}
    #SunHee

  2. Giải đáp $*$ Lời giải và giải thích chi tiết:
     a)(x^2)/(x-2) + (3x)/(x-2) – (x-4)/(x-2)
    =(x^2 +3x -x+4)/(x-2)
    =(x^2 +2x+4)/(x-2)
     b)2/(x^2 -1) + (x+1)/(x-1) -(x-1)/(x+1)
    =2/((x-1)(x+1)) + ((x+1)(x+1))/((x-1)(x+1)) – ((x-1)(x-1))/((x+1)(x-1))
    =(2+x^2 +2x+1 -x^2 +2x-1)/((x+1)(x-1))
    =(4x+2)/((x+1)(x-1))

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