1 Đúng hoặc Sai,nếu sai thì sửa lại cho đúng
a/\(\dfrac{5}{2\sqrt{5}}=\dfrac{\sqrt{5}}{2}\) ; b/\(\dfrac{2\sqrt{2}+2}{5\sqrt{2}}=\dfrac{2+\sqrt{2}}{10}\) ; c/\(\dfrac{2}{\sqrt{3}-1}=\sqrt{3}-1\) ; d/\(\dfrac{8}{2\sqrt{8}-1}=\dfrac{P\left(2\sqrt{8}+1\right)}{4P-1}\) ; e/\(\dfrac{1}{\sqrt{x}-\sqrt{y}}=\dfrac{\sqrt{x}+\sqrt{y}}{x-y}\)
2 Rút gọn các biểu thức
a/\(\dfrac{2+\sqrt{2}}{1+\sqrt{2}}\) ; b/\(\dfrac{a-\sqrt{a}}{1-\sqrt{a}}\) ; c/\(\dfrac{3+\sqrt{3}}{3-\sqrt{3}}+\dfrac{3-\sqrt{3}}{3+\sqrt{3}}\) ; d/\(\sqrt{\dfrac{3-\sqrt{5}}{3+\sqrt{5}}+\sqrt{\dfrac{3+\sqrt{5}}{3-\sqrt{5}}}}\)