Question

[Louis louis]

Rút gọn biểu thức:

a.\(\left(2\sqrt{3}-\sqrt{5}\right).\sqrt{3}+\sqrt{60}\)

b.\(\left(\sqrt{28}-\sqrt{12}-\sqrt{7}\right).\sqrt{7}+2\sqrt{21}\)

c.\(\left(2\sqrt{5}+\sqrt{50}\right).\sqrt{5}-\sqrt{250}\)

d.\(\left(3\sqrt{11}-\sqrt{18}-\sqrt{11}\right).\sqrt{11}+3\sqrt{22}\)

Answer 1

[Nguyễn Lê Phước Thịnh]

a: \(=6-\sqrt{15}+2\sqrt{15}=6+\sqrt{15}\)

b: \(=\left(\sqrt{7}-2\sqrt{3}\right)\cdot\sqrt{7}+2\sqrt{21}\)

\(=7-2\sqrt{21}+2\sqrt{21}=7\)

c: \(=10+5\sqrt{10}-5\sqrt{10}=10\)

d: \(=22-\sqrt{198}+\sqrt{198}=22\)