2\sqrt7- \(\frac{14}{\sqrt7} + \frac{7}{\sqrt21}\) L.C.M is \sqrt21 \(\frac{\sqrt21 * 2\sqrt7 - \sqrt3 *14 + 7}{\sqrt21}\) =\(\frac{2 * 7\sqrt3 - 14\sqrt3 + 7}{\sqrt21}\) = \(\frac{14\sqrt3 - 14\sqrt3 + 7}{\sqrt21}\) =\(\frac{7}{\sqrt21}\) or \(\frac{7 \times \sqrt21}{\sqrt21 \times \sqrt21}\) = \(\frac{7 \times \sqrt21}{21}\) or \(\frac{\sqrt21}{3}\)