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

Toán Lớp 8: Thực hiện phép tính: 1/3x-2 – 1/3x+2 – 3x+6/4-9x^2 :((

Toán Lớp 8: Thực hiện phép tính:
1/3x-2 – 1/3x+2 – 3x+6/4-9x^2
:((

Comments ( 2 )

  1. Giải đáp:
     
    Lời giải và giải thích chi tiết:
    $\frac{1}{3x – 2}$ – $\frac{1}{3x + 2}$ – $\frac{3x + 6}{4 – 9x²}$ 
    = $\frac{1}{3x – 2}$ – $\frac{1}{3x + 2}$ + $\frac{3x + 6}{9x² – 4}$ 
    = $\frac{1}{3x – 2}$ – $\frac{1}{3x + 2}$ + $\frac{3x + 6}{(3x – 2)(3x + 2)}$ 
    = $\frac{3x + 2}{(3x – 2)(3x + 2)}$ – $\frac{3x – 2}{(3x + 2)(3x – 2)}$ + $\frac{3x + 6}{(3x – 2)(3x + 2)}$ 
    = $\frac{3x + 2 – 3x + 2 + 3x + 6}{(3x – 2)(3x + 2)}$
    = $\frac{3x + 10}{(3x – 2)(3x + 2)}$

  2. Giải đáp:
    = {3x + 10}/{(3x – 2)(3x + 2)}
    Lời giải và giải thích chi tiết:
    1/{3x – 2} – 1/{3x + 2} – {3x + 6}/{4 – 9x^2}             (ĐKXĐ: x ne +- 3/2)
    = 1/{3x – 2} – 1/{3x + 2} – {3x + 6}/{- (9x^2 – 4)}
    = 1/{3x – 2} – 1/{3x + 2} + {3x + 6}/{9x^2 – 4}
    = 1/{3x – 2} – 1/{3x + 2} + {3x + 6}/{(3x)^2 – 2^2}
    = 1/{3x – 2} – 1/{3x + 2} + {3x + 6}/{(3x – 2)(3x + 2)}
    = {3x + 2}/{(3x – 2)(3x + 2)} – {3x – 2}/{(3x – 2)(3x + 2)} + {3x + 6}/{(3x – 2)(3x + 2)}
    = {3x + 2 – (3x – 2) + 3x + 6}/{(3x – 2)(3x + 2)}
    = {3x + 2 – 3x + 2 + 3x + 6}/{(3x – 2)(3x + 2)}
    = {(3x – 3x + 3x) + (6 + 2 + 2)}/{(3x – 2)(3x + 2)}
    = {3x + 10}/{(3x – 2)(3x + 2)}
    #SunHee

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