Help me :(((((((((((( l

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Help me :(((((((((((( l
help-me-l

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Hưng Khoa 5 years 2020-11-06T09:08:46+00:00 1 Answers 84 views 0

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  1. minhkhang
    0
    2020-11-06T09:10:31+00:00
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    Đáp án:

    i. \(TXD:D = \left[ { – 3; + \infty } \right)\backslash \left\{ { – 2;2} \right\}\)

    Giải thích các bước giải:

    \(\begin{array}{l}
    a.DK:2x – 3 \ge 0\\
     \to x \ge \dfrac{3}{2}\\
    TXD:D = \left[ {\dfrac{3}{2}; + \infty } \right)\\
    b.DK:12x – 31 \ge 0\\
     \to x \ge \dfrac{{31}}{{12}}\\
    TXD:D = \left[ {\dfrac{{31}}{{12}}; + \infty } \right)\\
    c.DK:\left\{ \begin{array}{l}
    4 – x \ge 0\\
    x + 1 \ge 0
    \end{array} \right. \to 4 \ge x \ge  – 1\\
    TXD:D = \left[ { – 1;4} \right]\\
    d.DK:\left\{ \begin{array}{l}
    x + 1 \ge 0\\
    x – 3 \ne 0
    \end{array} \right. \to \left\{ \begin{array}{l}
    x \ge  – 1\\
    x \ne 3
    \end{array} \right.\\
    TXD:D = \left[ { – 1; + \infty } \right)\backslash \left\{ 3 \right\}\\
    e.DK:\left\{ \begin{array}{l}
    x – 1 > 0\\
    x + 2 \ne 0
    \end{array} \right. \to x > 1\\
    TXD:D = \left( {1; + \infty } \right)\\
    f.DK:x + 2 \ge 0 \to x \ge  – 2\\
    TXD:D = \left[ { – 2; + \infty } \right)\\
    g,DK:\left\{ \begin{array}{l}
    5 – 2x \ge 0\\
    x – 2 \ne 0\\
    x + 1 > 0
    \end{array} \right. \to \left\{ \begin{array}{l}
    x \ne 2\\
    \dfrac{5}{2} \ge x >  – 1
    \end{array} \right.\\
    TXD:D = \left( { – 1;\dfrac{5}{2}} \right]\backslash \left\{ 2 \right\}\\
    h.DK:\left\{ \begin{array}{l}
    2x – 1 \ge 0\\
    3 – x > 0
    \end{array} \right. \to 3 > x > \dfrac{1}{2}\\
    TXD:D = \left( {\dfrac{1}{2};3} \right)\\
    i.DK:\left\{ \begin{array}{l}
    x + 3 \ge 0\\
    {x^2} – 4 \ne 0
    \end{array} \right.\\
     \to \left\{ \begin{array}{l}
    x \ge  – 3\\
    x \ne  \pm 2
    \end{array} \right.\\
    TXD:D = \left[ { – 3; + \infty } \right)\backslash \left\{ { – 2;2} \right\}
    \end{array}\)

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