a. \(2\sqrt{3}=\sqrt{4}.\sqrt{3}=\sqrt{12}\)
\(3\sqrt{2}=\sqrt{9}.\sqrt{2}=\sqrt{18}\)
Vì \(\sqrt{12}< \sqrt{18}\Rightarrow2\sqrt{3}< 3\sqrt{2}\)
b. \(-\dfrac{1}{3}\sqrt{63}=-\sqrt{\dfrac{1}{9}}\sqrt{63}=-\sqrt{7}\)
\(-2\sqrt{2}=-\sqrt{4}\sqrt{2}=-\sqrt{8}\)
Vì \(-\sqrt{7}>-\sqrt{8}\Rightarrow-\dfrac{1}{3}\sqrt{63}>-2\sqrt{2}\)