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

Toán Lớp 8: 1) x^2+2x+1 / x^3+x^2-x-1 2) 25-(3-x)^2 / x^2+4x+4 3) 2x^2-8x+8 / 2x-4 (Đề bài l

Toán Lớp 8: 1) x^2+2x+1 / x^3+x^2-x-1
2) 25-(3-x)^2 / x^2+4x+4
3) 2x^2-8x+8 / 2x-4 (Đề bài là Rút gọn Phân thức Đại số ạ)

Comments ( 1 )

  1. Giải đáp:
    1) 1/(x – 1)
    2) {8 – x}/{x + 2}
    3) x – 2
    Lời giải và giải thích chi tiết:
    1)
    {x^2 + 2x + 1}/{x^3 + x^2 – x – 1}
    = {(x + 1)^2}/{(x^3 + x^2) – (x + 1)}
    = {(x + 1)^2}/{x^2(x + 1) – (x + 1)}
    = {(x + 1)^2}/{(x + 1)(x^2 – 1)}
    = {(x + 1)^2}/{(x + 1)(x + 1)(x – 1)}
    = {(x + 1)^2}/{(x + 1)^2 (x – 1)}
    = 1/(x – 1)
    2)
    {25 – (3- x)^2}/{x^2 + 4x + 4}
    = {5^2 – (3- x)^2}/{x^2 + 2.x.2 + 2^2}
    = {(5 – 3 + x)(5 + 3 – x)}/{(x + 2)^2}
    = {(2+ x)(8 – x)}/{(x + 2)^2}
    = {(x + 2)(8 – x)}/{(x + 2)^2}
    = {8 – x}/{x + 2}
    3)
    {2x^2 – 8x + 8}/{2x – 4}
    = {2(x^2 – 4x + 4)}/{2(x – 2)}
    = {2(x^2 – 2.x.2 + 2^2)}/{2(x – 2)}
    = {2(x – 2)^2}/{2(x – 2)}
    = {x – 2}/1
    = x – 2
    #SunHee

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

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