a) (2x+3)2 = 9/121; b) (3x-1)3 = (-8)/27

Question

a) (2x+3)2 = 9/121;
b) (3x-1)3 = (-8)/27

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Delwyn 5 years 2020-11-29T01:08:34+00:00 2 Answers 113 views 0

Answers ( )

  1. minhkhang
    0
    2020-11-29T01:09:52+00:00
    Reply

    Đáp án:

     

    Giải thích các bước giải:

    a) `(2x+3)^2 = 9/121`

    `⇔ (2x+3)^2=(3/11)^2`

    `⇔` \(\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\) 

    `⇔` \(\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\) 

    b) `(3x-1)^3 = (-8)/27`

    `⇔ (3x-1)^3=(-2/3)^3`

    `⇔ 3x-1=-2/3`

    `⇔ 3x=1/3`

    `⇔ x=1/9`

  2. Amity
    0
    2020-11-29T01:10:29+00:00
    Reply

    a) $(2x+3)^2=\dfrac{9}{121}$

    \(↔\left[ \begin{array}{l}2x+3=\dfrac{3}{11}\\2x+3=-\dfrac{3}{11}\end{array} \right.\) 

    \(↔\left[ \begin{array}{l}2x=-\dfrac{30}{11}\\2x=-\dfrac{36}{11}\end{array} \right.\)

    \(↔\left[ \begin{array}{l}x=-\dfrac{15}{11}\\x=-\dfrac{18}{11}\end{array} \right.\)

    b) $(3x-1)^3=\dfrac{-8}{27}$

    $↔3x-1=\dfrac{-2}{3}$

    $↔3x=-\dfrac{2}{3}+1$

    $↔3x=\dfrac{1}{3}$

    $↔x=\dfrac{1}{3}:3$

    $↔x=\dfrac{1}{9}$

     

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