\(1,\\ a,=6\sqrt{3}+2\sqrt{3}-3\sqrt{3}=5\sqrt{3}\\ b,=\dfrac{2\left(\sqrt{5}+3\right)}{-4}=\dfrac{-\sqrt{5}-3}{2}\\ c,\sqrt{\dfrac{3}{7}}=\dfrac{\sqrt{21}}{7}\\ d,ĐK:2x-1\ge0\Leftrightarrow x\ge\dfrac{1}{2}\\ 2,\\ a,=\sqrt{5}-2+1-\sqrt{5}=-1\\ b,=2a-1+\sqrt{\left(1-a\right)^2}=2a-1+\left|1-a\right|\\ =2a-1+1-a=a\\ 3,\\ ĐK:x\ge0\\ PT\Leftrightarrow6\sqrt{3x}-2\sqrt{3x}=8\\ \Leftrightarrow4\sqrt{3x}=8\Leftrightarrow\sqrt{3x}=2\Leftrightarrow3x=4\\ \Leftrightarrow x=\dfrac{4}{3}\left(tm\right)\)
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