Question

Rút gọn: \(\sqrt{30-10\sqrt{5}}\)

Answer 1

\(\sqrt{30-10\sqrt{5}}=\sqrt{25-2.5\sqrt{5}+5}=5-\sqrt{5}\)

Answer 2

\(\sqrt{30-10\sqrt{5}}\)

\(=\sqrt{\left(\sqrt{5}\right)^2-2.5.\sqrt{5}+5^2}\)

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

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

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

\(=-\sqrt{5}+5\)

Answer 3

\(=\sqrt{25-2.5.\sqrt{5}+5}=\sqrt{\left(5-\sqrt{5}\right)^2=5-\sqrt{5}}\)