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

Toán Lớp 8: [(3x-1/x^2 -9) – (1/3-x)] : 2x+1/ x-3

Home/ Toán Lớp 8: [(3x-1/x^2 -9) – (1/3-x)] : 2x+1/ x-3

Toán Lớp 8: [(3x-1/x^2 -9) – (1/3-x)] : 2x+1/ x-3

Tháng Bảy 30, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: [(3x-1/x^2 -9) – (1/3-x)] : 2x+1/ x-3

Comments ( 2 )

  1. thanhmaianh
    thanhmaianh
    30 Tháng Bảy, 2022 at 9:30 chiều
    Reply
    Giải đáp:
    = 2/{x+ 3}
    Lời giải và giải thích chi tiết:
    [({3x – 1}/{x^2 – 9}) – 1/{3 – x})] : {2x + 1}/{x – 3}
    =[({3x – 1}/{x^2 – 3^2}) – ({-1}/{x – 3})] : {2x + 1}/{x – 3}
    =[{3x – 1}/{(x – 3)(x + 3)) – {-1}/{x – 3}] : {2x + 1}/{x – 3}
    =[{3x – 1}/{(x – 3)(x + 3)} + {x + 3}/{(x – 3)(x + 3)}] : {2x + 1}/{x – 3}
    ={3x – 1+ x + 3}/{(x – 3)(x + 3)} : {2x + 1}/{x – 3}
    ={4x + 2}/{(x – 3)(x + 3)} : {2x + 1}/{x – 3}
    = {2(2x + 1)}/{(x – 3)(x + 3)} . {x – 3}/{2x + 1}
    = {2.1}/{x + 3} . {1}/{1}
    = 2/{x+ 3}
    #SunHee

  2. maianh67
    maianh67
    30 Tháng Bảy, 2022 at 9:30 chiều
    Reply
    Gửi bạn:
    $(\dfrac{3x-1}{x^2-9}-\dfrac{1}{3-x}):\dfrac{2x+1}{x-3}$ 
    $=(\dfrac{3x-1}{(x-3)(x+3)}+\dfrac{1}{x-3}):\dfrac{2x+1}{x-3}$ 
    $=(\dfrac{3x-1}{(x-3)(x+3)}+\dfrac{x+3}{(x-3)(x+3)}):\dfrac{2x+1}{x-3}$ 
    $=\dfrac{3x-1+x+3}{(x-3)(x+3)}:\dfrac{2x+1}{x-3}$ 
    $=\dfrac{2(2x+1)}{(x+3)(2x+1)}$ 
    $=\dfrac{2}{(x+3)}$ 

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

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