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

Toán Lớp 8: Thực Hiện Phép Tính a. 1/ 2x+2 – (x-1/3×2+6x+3) b. 1/3x-2 – 4/3x-2- 3x-6/4-9×2

Home/ Toán Lớp 8: Thực Hiện Phép Tính a. 1/ 2x+2 – (x-1/3×2+6x+3) b. 1/3x-2 – 4/3x-2- 3x-6/4-9×2

Toán Lớp 8: Thực Hiện Phép Tính a. 1/ 2x+2 – (x-1/3×2+6x+3) b. 1/3x-2 – 4/3x-2- 3x-6/4-9×2

Tháng Bảy 25, 2022 Toán học 2 Comments 0 views

Toán Lớp 8: Thực Hiện Phép Tính
a. 1/ 2x+2 – (x-1/3×2+6x+3)
b. 1/3x-2 – 4/3x-2- 3x-6/4-9×2

Comments ( 2 )

  1. lantrungbach
    lantrungbach
    25 Tháng Bảy, 2022 at 11:30 sáng
    Reply
    $\dfrac{1}{2x+2}$ -$\dfrac{x-1}{3x^2+6x+3}$ 
    ĐKXĐ : $\begin{cases}2x+2\neq0 \\3x^2+6x+3\neq0\end{cases}$
    => x $\neq$ -1 ; x$\neq$ $\dfrac{-1}{3}$ 
    = $\dfrac{1}{2(x+1)}$ -$\dfrac{x-1}{3(x^2+2x+1)}$  
    = $\dfrac{1}{2(x+1)}$ -$\dfrac{x-1}{3(x+1)^2}$  
    = $\dfrac{3(x+1)}{6(x+1)^2}$ -$\dfrac{2x-2}{6(x+1)^2}$ 
    = $\dfrac{3x+3-2x+2}{6(x+1)^2}$
    = $\dfrac{x+5}{6(x+1)^2}$
    b) $\dfrac{1}{3x-2}$ -$\dfrac{4}{3x+2}$ -$\dfrac{3x-6}{4-9x^2}$ 
    ĐKXĐ : x$\neq$ $±\dfrac{2}{3}$ 
    = $\dfrac{3x+2}{(3x+2)(3x-2)}$ -$\dfrac{4(3x-2)}{(3x+2)(3x-2)}$ +$\dfrac{3x-6}{(3x+2)(3x-2)}$ 
    = $\dfrac{3x+2-12x+8+3x-6}{(3x+2)(3x-2)}$
    =$\dfrac{-6x+4}{(3x+2)(3x-2)}$
    =$\dfrac{-2(3x-2)}{(3x+2)(3x-2)}$
    =$\dfrac{-2}{3x+2}$ 

  2. diemmyhoa
    diemmyhoa
    25 Tháng Bảy, 2022 at 11:29 sáng
    Reply
    Giải đáp:
    a)
    1/(2x+2)-(x-1)/(3x^(2)+6x+3)     (ĐK : x \ne -1)
    =1/[2(x+1)]-(x-1)/(3x^(2)+3x+3x+3)
    =1/[2(x+1)]-(x-1)/[3.(x+1)(x+1)]
    =[3.(x+1)]/[6(x+1)^2]-(2.(x-1))/[6(x+1)^2]
    =(3x+3-2x+2)/[6(x+1)^2]
    =(x+5)/[6(x+1)^2]
    b)
    1/(3x-2)-4/(3x+2)-(3x-6)/(4-9x^2)    (ĐK : x \ne +-2/3)
    =(3x+2)/[(3x+2)(3x-2)]-[4(3x-2)]/[(3x-2)(3x+2)]+(3x-6)/[(3x-2)(3x+2)]
    =(3x+2-12x+8+3x-6)/[(3x-2)(3x+2)]
    =(-6x+4)/[(3x-2)(3x+2)]
    =[-2(3x-2)]/[(3x-2)(3x+2)]
    =-2/(3x+2)
     

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

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