a: \(=6\cdot\dfrac{2\sqrt{2}}{3}-5\cdot\dfrac{4\sqrt{2}}{5}+14\cdot\dfrac{3\sqrt{2}}{7}\)
\(=4\sqrt{2}-4\sqrt{2}+6\sqrt{2}=6\sqrt{2}\)
b: \(=2\cdot\dfrac{4}{\sqrt{3}}-3\cdot\dfrac{1}{3\sqrt{3}}-6\cdot\dfrac{2}{5\sqrt{3}}\)
\(=\dfrac{8}{\sqrt{3}}-\dfrac{1}{\sqrt{3}}-\dfrac{12}{5}\cdot\dfrac{1}{\sqrt{3}}=\dfrac{23}{5\sqrt{3}}=\dfrac{23\sqrt{3}}{15}\)
c: \(=3\sqrt{2}+2\sqrt{2}+\dfrac{1}{5}\cdot5\sqrt{2}-4\sqrt{2}\)
\(=\sqrt{2}+\sqrt{2}=2\sqrt{2}\)