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

Toán Lớp 8: x+1/x-3 -1-x/x+3-2x(1-x)/9-x^2 Trừ phân thức

Tháng Tư 30, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: x+1/x-3 -1-x/x+3-2x(1-x)/9-x^2
Trừ phân thức

Comments ( 2 )

  1. tonhitruc
    tonhitruc
    30 Tháng Tư, 2022 at 1:10 chiều
    Reply
    Giải đáp:
    = 2/{x – 3}
    Lời giải và giải thích chi tiết:
    {x+1}/{x-3}-{1-x}/{x+3}-{2x(1-x)}/{9-x^2}
    = {x+1}/{x-3}-{1-x}/{x+3}-{2x(1-x)}/{- (x^2-9)}
    ={x+1}/{x-3}-{1-x}/{x+3}+{2x(1-x)}/{x^2-9}
    ={x+1}/{x-3}-{1-x}/{x+3}+{2x(1-x)}/{x^2-3^2}
    ={x+1}/{x-3} – {1-x}/{x+3}+{2x(1-x)}/{(x – 3)(x + 3)}
    = {(x+1)(x + 3)}/{(x – 3)(x + 3)} – {(1-x)(x – 3)}/{(x – 3)(x + 3)}+{2x(1-x)}/{(x – 3)(x + 3)}
    ={x^2 + 3x + x + 3}/{(x – 3)(x + 3)} – {x – 3 – x^2 + 3x}/{(x – 3)(x + 3)}+{2x-2x^2}/{(x – 3)(x + 3)}
    ={x^2 + 4x + 3}/{(x – 3)(x + 3)} – {- x^2 + 4x – 3}/{(x – 3)(x + 3)}+{2x-2x^2}/{(x – 3)(x + 3)}
    ={x^2 + 4x + 3-(-x^2 + 4x – 3)+ 2x – 2x^2}/{(x – 3)(x + 3)}
    = {x^2 + 4x + 3 + x^2 – 4x +3+ 2x – 2x^2}/{(x – 3)(x + 3)}
    = {(x^2 + x^2 – 2x^2) + (4x – 4x + 2x) + (3 + 3)}/{(x – 3)(x + 3)}
    = {2x + 6}/{(x – 3)(x + 3)}
    = {2(x + 3)}/{(x – 3)(x + 3)}
    = 2/{x – 3}
    #SunHee

  2. hatuanlan
    hatuanlan
    30 Tháng Tư, 2022 at 1:10 chiều
    Reply
    Giải đáp:
    $\frac{x+1}{x – 3}$ – $\frac{1-x}{x +3}$- $\frac{2x(1-x)}{9-x^2}$
    = $\frac{(x+1)}{(x+3)}$ + $\frac{(x+1)(x-3)}{x^2 -3^2}$ – $\frac{2x(x-1)}{x^2-3^2}$ 
     = $\frac{(x+1)(x+3) + (x+1)(x-3)-2x(x+1) }{x^2 -3^2}$
    =$\frac{(x+1)(x+3 + x -3 – 2x)}{x^2 – 3^2 }$
    = $\frac{x+1}{x^2 – 3^2}$

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

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