Câu a :
\(\dfrac{\sqrt{15}-10\sqrt{2}-\sqrt{10}}{\sqrt{5}}\)
\(=\dfrac{\sqrt{5}\left(\sqrt{3}-\sqrt{40}-\sqrt{2}\right)}{\sqrt{5}}\)
\(=\sqrt{3}-\sqrt{40}-\sqrt{2}\)
Câu b :
\(\dfrac{\sqrt{8}-4\sqrt{3}}{\sqrt{2}}\)
\(=\dfrac{\sqrt{2}\left(\sqrt{4}-\sqrt{24}\right)}{\sqrt{2}}\)
\(=\sqrt{4}-\sqrt{24}\)
Wish you study well !!