Tìm x a,-$x^{2}$+234=0 b,16$x^{2}$-5=0 c,2/$\sqrt[]{x-3}$=4 d,$\sqrt[]{4x^{2}-4x+1 }$ =3 e,$\sqrt[]{x+3}$ $\geq$ 5 f,$\sqrt[]{-2x}$+1>7 g,$\sqrt[]{x

0 bình luận về “Tìm x a,-$x^{2}$+234=0 b,16$x^{2}$-5=0 c,2/$\sqrt[]{x-3}$=4 d,$\sqrt[]{4x^{2}-4x+1 }$ =3 e,$\sqrt[]{x+3}$ $\geq$ 5 f,$\sqrt[]{-2x}$+1>7 g,$\sqrt[]{x”

1. a)

   `-x^2=234`

   `⇔x^2=-234`

   `⇒x=∅`

   b)

   `16x^2-5=0`

   `⇔16x^2=5`

   `⇔x^2=5/16`

   `⇔x=\sqrt{5}/4`

   c) ĐKXD:`x≥3`

   `2/\sqrt{x-3}=4`

   `⇔\sqrt{x-3}=1/2`

   `⇔x-3=1/4`

   `⇔x=13/4`

   d)

   `\sqrt{4x^2-4x+1}=3`

   `⇔\sqrt{(2x-1)^2}=3`

   `⇔|2x-1|=3`

   `⇔`\(\left[ \begin{array}{l}2x-1=3\\2x-1=-3\end{array} \right.\) 

   `⇔`\(\left[ \begin{array}{l}2x=4\\2x=-2\end{array} \right.\) 

   `⇔`\(\left[ \begin{array}{l}x=2\\x=-1\end{array} \right.\) 

   e)

   `\sqrt{x+3}≥5`

   `⇔x+3≥25 `

   `⇔x≥22`

   f)ĐKXD:`x≤0`

   `\sqrt{-2x}+1>7`

   `⇔\sqrt{-2x}>6`

   `⇔-2x>36`

   `⇔x> -18`

   `⇔-18<x≤0`

   g)ĐKXD:`x≥0`

   `\sqrt{x}+9<31`

   `⇔\sqrt{x}<22`

   `⇔x<484`

   `⇔0≤x<484`

   h)ĐKXD:`x≥1/3`

   `\sqrt{3x-1}<2`

   `⇔3x-1<4`

   `⇔3x<5`

   `⇔x<5/3`

   `⇔1/3≤x<5/3`

    

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2. Đáp án:

    

   Giải thích các bước giải:

    

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