Tìm x bt (2x-1)^3=2x-1

Question

Tìm x bt
(2x-1)^3=2x-1

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Hồng Cúc 5 years 2021-05-20T16:39:07+00:00 2 Answers 29 views 0

Answers ( )

  1. haidang
    0
    2021-05-20T16:40:25+00:00
    Reply

    $#Dino$

    `(2x-3)^3=2x-1`

    `⇒(2x-1)^3-(2x-1)=0`

    `⇒(2x-1)[(2x-1)²-1]=0`

    `⇒(2x-1)(2x-1-1)(2x-1+1)=0`

    `⇒2x(2x-1)(2x-2)=0`

    `1) 2x=0⇒x=0`

    `2) 2x-1=0⇒x=1/2`

    `3) 2x-2=0⇒x=1`

    Vậy `x∈{0;1;1/2}`

     

  2. Giakhanh
    0
    2021-05-20T16:40:49+00:00
    Reply

    Đáp án:

     

    Giải thích các bước giải:

     `⇔(2x-1)^3-(2x-1)=0`

    `⇔(2x-1)[(2x-1)^2-1]=0`

    `⇔TH1:2x-1=0`

    `⇔2x=1`

    `⇔x=1/2`

    `TH2:(2x-1)^2 -1=0`

    `(2x-1)^2 =1^2`

    `⇔2x-1=1` hoặc `2x-1=-1`

    `⇔2x=2`

    `⇔x=1`

    Hoặc `2x-1=-1`

    `⇔2x=0`

    `⇔x=0`

    `=>S={1;1/2 ;0}`

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Giải phương trình 1 ẩn: x + 2 - 2(x + 1) = -x . Hỏi x = ? ( )