Question

thực hiện phép tính

a)\(\sqrt{80}-\sqrt{\left(2-\sqrt{5}\right)^2}+\sqrt{3\dfrac{1}{5}}\)

b)\(\dfrac{\sqrt{6}-\sqrt{3}}{1-\sqrt{2}}+\dfrac{3+6\sqrt{3}}{\sqrt{3}}-\dfrac{13}{\sqrt{3}+4}\)

Answer 1

a: \(=4\sqrt{5}-\left|2-\sqrt{5}\right|+\sqrt{\dfrac{16}{5}}\)

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

\(=\dfrac{19}{5}\sqrt{5}+2\)

b: \(=\dfrac{-\sqrt{3}\left(1-\sqrt{2}\right)}{1-\sqrt{2}}+\dfrac{\sqrt{3}\left(6+\sqrt{3}\right)}{\sqrt{3}}-\dfrac{13\left(4-\sqrt{3}\right)}{\left(4-\sqrt{3}\right)\left(4+\sqrt{3}\right)}\)

\(=-\sqrt{3}+6+\sqrt{3}-4+\sqrt{3}=2+\sqrt{3}\)