2√7- 147+ 721\;\frac{14}{\sqrt{7}} + \;\frac{7}{\sqrt{21}}714+217
L.C.M is √21
21 ⋅ 27 − 3 ⋅14 + 721\;\frac{\sqrt{21}\;\cdot\;2\sqrt{7}\;\;-\;\sqrt{3}\;\cdot14\;\;+\;7}{\sqrt{21}}2121⋅27−3⋅14+7
= 2 ⋅ 73 − 143 + 721\;\frac{2\;\cdot\;7\sqrt{3}\;-\;14\sqrt{3}\;+\;7}{\sqrt{21}}212⋅73−143+7
= 143 − 143 + 721\;\frac{14\sqrt{3}\;-\;14\sqrt{3}\;+\;7}{\sqrt{21}}21143−143+7
= 721\;\frac{7}{\sqrt{21}}217
or
7 × 2121 × 21\;\frac{7\;\times\;\sqrt{21}}{\sqrt{21}\;\times\;\sqrt{21}}21×217×21
= 7 × 2121\;\frac{7\;\times\;\sqrt{21}}{21}217×21 or 213\;\frac{\sqrt{21}}{3}321
