Tìm x, biết A,(x- √3)= (1- √3 ) B, (x + 4 ) = 2√2 C, √1,69. (2√x + √81/121 ) =13/10 D,x- 5 √x =0
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Đáp án:
Giải thích các bước giải: 1. (- $\sqrt{3}$ ) + (- $\sqrt{3}$ ) => x=1
2. <=> x = 4+2 $\sqrt{2}$
3.<=> 2 $\sqrt{x}$ + 9/11 =1.3/1.3
<=> 2 $\sqrt{x}$ = 2/11
<=> $\sqrt{x}$ = 1/11
<=> x = (1/11)^2 = 1/121
4.<=> x=0
A, \((x-\sqrt{3})=(1-\sqrt{3})\Leftrightarrow x=(1- \sqrt{3}) +\sqrt{3} \Leftrightarrow x=1\) B, \(x+4=2\sqrt{2}\Leftrightarrow x = 2 \sqrt{2}-4 \) C, \(\sqrt{1,69}\left({2\sqrt{x}+\sqrt{\dfrac{81}{121}}}\right)=\dfrac{13}{10}\) \(\Leftrightarrow 1,3\left({2\sqrt{x}+\dfrac{9}{11} }\right)= 1,3\) \(\Leftrightarrow 2\sqrt{x}+\dfrac{9}{11} = \dfrac{1,3}{1,3}\) \(\Leftrightarrow 2 \sqrt{x} = 1-\dfrac{9}{11}\) \(\Leftrightarrow \sqrt{x} = \dfrac{2}{11.2}\) \(\Leftrightarrow x=\dfrac{1}{121}\) D, \(x-5\sqrt{x}=0\Leftrightarrow \sqrt{x}(\sqrt{x}-5)=0\) \(\Leftrightarrow\left[\begin{array}{l} \sqrt{x}=0 \\ \sqrt{x}=5 \end{array} \right .\) \(\Leftrightarrow\left[\begin{array}{l} x=0 \\ x=25 \end{array} \right .\)
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