(x – 2) (x + 5) = 0 (20 – x)/10 = x/5

Question

(x – 2) (x + 5) = 0
(20 – x)/10 = x/5

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Adela 9 months 2021-05-07T03:56:57+00:00 2 Answers 7 views 0

Answers ( )

    0
    2021-05-07T03:58:12+00:00

    Đáp án:

    a) `x in {-5;2}`

    b) `x=20/3` 

    Giải thích các bước giải:

    a)

    `(x-2).(x+5)=0`

    `to`  \(\left[ \begin{array}{l}x-2=0\\x+5=0\end{array} \right.\) `to`\(\left[ \begin{array}{l}x=2\\x=-5\end{array} \right.\) 

    Vậy `x in {-5;2}`

    b)

    `(20-x)/10=x/5`

    `to 5.(20-x)=10x`

    `to 100-5x=10x`

    `to 100=10x+5x`

    `to 100=15x`

    `to x=100/15=20/3`

    Vậy `x=20/3`

    0
    2021-05-07T03:58:56+00:00

    Đáp án+Giải thích các bước giải:

     `(x-2)(x+5)=0`

    \(⇔\left[ \begin{array}{l}x-2=0\\x+5=0\end{array} \right.\)

    \(⇔\left[ \begin{array}{l}x=0+2\\x=0-5\end{array} \right.\)

    \(⇔\left[ \begin{array}{l}x=2\\x=-5\end{array} \right.\)

    Vậy `x\in\{2;-5\}`

    `(20-x)/10=x/5`

    `⇔5(20-x)=10.x`

    `⇔100-5x=10x`

    `⇔10x+5x=100`

    `⇔15x=100`

    `⇔x=100/15`

    `⇔x=20/3`

    Vậy `x=20/3`

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