Giải phương trình a, 4(x+2) – 1 = x-5 b, 2/x+1 – 1/x-2 = 3x -11/(x+1)(x-2) c, (x-2)(2x-1) = 5(x-2) Giải hộ tớ với ạ

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Giải phương trình
a, 4(x+2) – 1 = x-5
b, 2/x+1 – 1/x-2 = 3x -11/(x+1)(x-2)
c, (x-2)(2x-1) = 5(x-2)
Giải hộ tớ với ạ

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Nevaeh 1 giờ 2021-09-07T10:35:21+00:00 2 Answers 0 views 0

Answers ( )

    0
    2021-09-07T10:36:29+00:00

    `a)4(x+2)-1=x-5`

    `<=>4x+8-1=x-5`

    `<=>3x=-12`

    `<=>x=-4`

    `b)2(x+1)-1/(x-2)=(3x-11)/((x+1)(x-2))`

    `=>2(x-2)-1(x+1)=3x-11`

    `<=>2x-4-x-1=3x-11`

    `<=>-2x=-6`

    `<=>x=3`

    `c)(x-2)(2x-1)=5(x-2)`

    `<=>(x-2)(2x-1)-5(x-2)=0`

    `<=>(x-2)(2x-1-5)=0`

    `<=>(x-2)(2x-6)=0`

    `<=>2(x-2)(x-3)=0`

    `<=>`\(\left[ \begin{array}{l}x=2\\x=3\end{array} \right.\) 

    0
    2021-09-07T10:36:54+00:00

    Đáp án+Giải thích các bước giải:

     `a)4(x+2)-1=x-5`

    `⇔4x+8-1=x-5`

    `⇔4x+7=x-5`

    `⇔4x-x=-5-7`

    `⇔3x=-12`

    `⇔x=-4`

    Vậy `S=\{-4\}`

    `b)ĐKXĐ:x\ne -1;x\ne 2`

    `2/(x+1)-1/(x-2)=(3x-11)/((x+1)(x-2))`

    `⇔(2(x-2))/((x+1)(x-2))-(1(x+1))/((x-2)(x+1))=(3x-11)/((x+1)(x-2))`

    `⇒2(x-2)-(x+1)=3x-11`

    `⇔2x-4-x-1=3x-11`

    `⇔x-5=3x-11`

    `⇔3x-x=-5+11`

    `⇔2x=6`

    `⇔x=3(TM)`

    Vậy `S=\{3\}`

    `c)(x-2)(2x-1)=5(x-2)`

    `⇔(x-2)(2x-1)-5(x-2)=0`

    `⇔(x-2)[(2x-1)-5]=0`

    `⇔(x-2)(2x-1-5)=0`

    `⇔(x-2)(2x-6)=0`

    \(⇔\left[ \begin{array}{l}x-2=0\\2x-6=0\end{array} \right.\)

    \(⇔\left[ \begin{array}{l}x=2\\2x=6\end{array} \right.\)

    \(⇔\left[ \begin{array}{l}x=2\\x=3\end{array} \right.\)

    Vậy `S=\{2;3\}`

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