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Mathematics

Simplify :

71723317+23\dfrac{7}{\sqrt{17} - 2\sqrt{3}} - \dfrac{3}{\sqrt{17} + 2\sqrt{3}}

Rational Irrational Nos

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Answer

71723317+23=7×(17+23)3×(1723)(1723)×(17+23)=(717+143)(31763)(17)2(23)2=717+143317+631712=417+2035\dfrac{7}{\sqrt{17} - 2\sqrt{3}} - \dfrac{3}{\sqrt{17} + 2\sqrt{3}}\\[1em] = \dfrac{7 \times (\sqrt{17} + 2\sqrt{3}) - 3 \times (\sqrt{17} - 2\sqrt{3})}{(\sqrt{17} - 2\sqrt{3}) \times (\sqrt{17} + 2\sqrt{3})} \\[1em] = \dfrac{(7\sqrt{17} + 14\sqrt{3}) - (3\sqrt{17} - 6\sqrt{3})}{(\sqrt{17})^2 - (2\sqrt{3})^2}\\[1em] = \dfrac{7\sqrt{17} + 14\sqrt{3} - 3\sqrt{17} + 6\sqrt{3}}{17 - 12}\\[1em] = \dfrac{4\sqrt{17} + 20\sqrt{3}}{5}

Hence, 71723317+23=417+2035\dfrac{7}{\sqrt{17} - 2\sqrt{3}} - \dfrac{3}{\sqrt{17} + 2\sqrt{3}} = \dfrac{4\sqrt{17} + 20\sqrt{3}}{5}.

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