1.
a, \(\sqrt{2}\left(\sqrt{2}-\sqrt{3-\sqrt{5}}\right)\)
\(=2-\sqrt{6-2\sqrt{5}}\)
\(=2-\sqrt{\left(\sqrt{5}-1\right)^2}\)
\(=2-\sqrt{5}+1\)
\(=3-\sqrt{5}\)
1.
b, ĐK: \(x\ge0;x\ne4\)
\(\dfrac{x-2\sqrt{x}}{\sqrt{x}-2}=\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{\sqrt{x}-2}=\sqrt{x}\)
a: \(\sqrt{2}\cdot\left(\sqrt{2}-\sqrt{3-\sqrt{5}}\right)\)
\(=2-\sqrt{6-2\sqrt{5}}\)
\(=2-\sqrt{5}+1\)
\(=3-\sqrt{5}\)
b: \(\dfrac{x-2\sqrt{x}}{\sqrt{x}-2}=\dfrac{\sqrt{x}\left(\sqrt{x}-2\right)}{\sqrt{x}-2}=\sqrt{x}\)
