Question

rút gọn biểu thức

\(\dfrac{\sqrt{9-4\sqrt{5}}}{2-\sqrt{5}}\)

Answer 1

\(\dfrac{\sqrt{9-4\sqrt{5}}}{2-\sqrt{5}}=\dfrac{\sqrt{\left(\sqrt{5}-2\right)^2}}{2-\sqrt{5}}=\dfrac{\sqrt{5}-2}{2-\sqrt{5}}=\dfrac{-\left(2-\sqrt{5}\right)}{2-\sqrt{5}}=-1\)

Answer 2

\(\dfrac{\sqrt{9-4\sqrt{5}}}{2-\sqrt{5}}=-1\)