Question

Tính

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

Answer 1

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

Answer 2

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

\(=\left|\sqrt{5}-2\right|-\sqrt{5}=\sqrt{5}-2-\sqrt{5}=-2\)

đây nè bạn !

Answer 3

dễ mà