a: \(=\dfrac{\sqrt{2}}{2}\)
\(\dfrac{1}{\sqrt{3}}=\dfrac{\sqrt{3}}{3}\)
\(\dfrac{1}{\sqrt{5}}=\dfrac{\sqrt{5}}{5}\)
\(\dfrac{1}{\sqrt{7}}=\dfrac{\sqrt{7}}{7}\)
b: \(\dfrac{3}{\sqrt{3}}=\sqrt{3}\)
\(\dfrac{12}{5\sqrt{3}}=\dfrac{2\sqrt{3}}{5}\)
\(\dfrac{14}{\sqrt{7}}=2\sqrt{7}\)