Question

[Nguyễn Mary]

Bài 1: rút gọn

I=\(\sqrt{4+\sqrt{10+2\sqrt{5}}}+\sqrt{4-\sqrt{10+2\sqrt{5}}}\)

K=\(\sqrt{94-42\sqrt{5}}-\sqrt{94+42\sqrt{5}}\)

Bài 2: tính

Y=\(2+\sqrt{17-4\sqrt{9+4\sqrt{5}}}\)

Z=\(\sqrt[3]{7+5\sqrt{2}}+\sqrt[3]{7-5\sqrt{2}}\)

T=\(\sqrt{3-\sqrt{5}}\left(3+\sqrt{5}\right)\left(\sqrt{10}-\sqrt{2}\right)\)

Answer 1

[Nguyễn Lê Phước Thịnh]

Câu 2: 

a: \(=2+\sqrt{17-4\left(\sqrt{5}+2\right)}\)

\(=2+\sqrt{17-4\sqrt{5}-8}\)

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

\(=2+\sqrt{5}-2=\sqrt{5}\)

b: \(=\sqrt{2}+1+1-\sqrt{2}=2\)

c: \(=\sqrt{6-2\sqrt{5}}\cdot\left(3+\sqrt{5}\right)\left(\sqrt{5}-1\right)\)

\(=\left(6-2\sqrt{5}\right)\left(3+\sqrt{5}\right)\)

\(=18+6\sqrt{5}-6\sqrt{5}-10=8\)