a) √3x-2=2- √3 b) ³ √x-5=0,9 c) √4x+20 – 3 √5+x + 4\3 √9x+45=6 d) √2x-25 – 15\2 √x-1\9= 6+ √x-1

0 bình luận về “a) √3x-2=2- √3 b) ³ √x-5=0,9 c) √4x+20 – 3 √5+x + 4\3 √9x+45=6 d) √2x-25 – 15\2 √x-1\9= 6+ √x-1”

1. a) $\sqrt{3x-2}=2-\sqrt3$

   ĐK: $3x-2\ge0\Rightarrow x\ge\dfrac{2}{3}$

   Phương trình suy ra:

   $3x-2=4-4\sqrt3+3$

   $\Rightarrow x=\dfrac{9-4\sqrt3}{3}$ ™

   b) $\sqrt[3]{x-5}=0,9$

   $\Rightarrow x-5=0,9^3$

   $\Rightarrow x=0,725+5$

   $\Rightarrow x=5,725$

   c) $\sqrt{4x+20} – 3 \sqrt{5+x} + \dfrac{4}{3}\sqrt {9x+45}=6$ ĐK: $x\ge-5$

   $\Rightarrow 2\sqrt{x+5}-3\sqrt{x+5}+\dfrac{4}{3}.3\sqrt{x+5}=6$

   $\Rightarrow 3\sqrt{x+5}=6$

   $\Rightarrow x+5=2^2$

   $\Rightarrow x=-1$ ™

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