\(D=\sqrt{75}-\sqrt{12}-\dfrac{2}{\sqrt{3}}=\sqrt{3.25}-\sqrt{3.4}-\dfrac{2\sqrt{3}}{3}=5\sqrt{3}-2\sqrt{3}-\dfrac{2\sqrt{3}}{3}\)
\(3\sqrt{3}-\dfrac{2\sqrt{3}}{3}=\dfrac{9\sqrt{3}-2\sqrt{3}}{3}=\dfrac{7\sqrt{3}}{3}\)
\(\sqrt{75}-\sqrt{12}-\dfrac{2}{\sqrt{3}}\)
= \(5\sqrt{3}-2\sqrt{3}-\dfrac{2\sqrt{3}}{3}\)
=\(\left(5-2-\dfrac{2}{3}\right)\sqrt{3}\)
=\(\dfrac{7\sqrt{3}}{3}\)