Bonjour Lulu111
Exercice 78
[tex]\dfrac{3}{\sqrt{2}}=\dfrac{3\sqrt{2}}{\sqrt{2}\sqrt{2}}=\dfrac{3\sqrt{2}}{2}\\\\\\\dfrac{-1}{\sqrt{7}}=\dfrac{-\sqrt{7}}{\sqrt{7}\sqrt{7}}=\dfrac{-\sqrt{7}}{7}\\\\\\\dfrac{7}{2\sqrt{5}}=\dfrac{7\sqrt{5}}{2\sqrt{5}\sqrt{5}}=\dfrac{7\sqrt{5}}{2\times5}=\dfrac{7\sqrt{5}}{10}\\\\\\\dfrac{4\sqrt{2}}{\sqrt{3}}=\dfrac{4\sqrt{2}\sqrt{3}}{\sqrt{3}\sqrt{3}}=\dfrac{4\sqrt{6}}{3}[/tex]
[tex]\\\\\\\dfrac{-3\sqrt{3}}{5\sqrt{6}}=\dfrac{-3\sqrt{3}}{5\sqrt{3}\sqrt{2}}=\dfrac{-3}{5\sqrt{2}}=\dfrac{-3\sqrt{2}}{5\sqrt{2}\sqrt{2}}=\dfrac{-3\sqrt{2}}{5\times2}=\dfrac{-3\sqrt{2}}{10}[/tex]
Exercice 79
[tex]\dfrac{-10}{\sqrt{11}}=\dfrac{-10\sqrt{11}}{\sqrt{11}\sqrt{11}}=\dfrac{-10\sqrt{11}}{11}\\\\\\\dfrac{5\sqrt{2}-1}{\sqrt{7}}=\dfrac{(5\sqrt{2}-1)\sqrt{7}}{\sqrt{7}\sqrt{7}}=\dfrac{5\sqrt{2}\sqrt{7}-\sqrt{7}}{7}=\dfrac{5\sqrt{14}-\sqrt{7}}{7}\\\\\\\dfrac{-3+\sqrt{2}}{2\sqrt{5}}=\dfrac{(-3+\sqrt{2})\sqrt{5}}{2\sqrt{5}\sqrt{5}}=\dfrac{-3\sqrt{5}+\sqrt{2}\sqrt{5}}{2\sqrt{5}\sqrt{5}}=\dfrac{-3\sqrt{5}+\sqrt{10}}{2\times5}\\\\=\dfrac{-3\sqrt{5}+\sqrt{10}}{10}[/tex]
[tex]\dfrac{4-\sqrt{7}}{-3\sqrt{2}}=\dfrac{(4-\sqrt{7})\sqrt{2}}{-3\sqrt{2}\sqrt{2}}=\dfrac{4\sqrt{2}-\sqrt{7}\sqrt{2}}{-3\times2}=\dfrac{4\sqrt{2}-\sqrt{14}}{-6}=\dfrac{\sqrt{14}-4\sqrt{2}}{6}\\\\\\\dfrac{11-7\sqrt{5}}{3\sqrt{11}}=\dfrac{(11-7\sqrt{5})\sqrt{11}}{3\sqrt{11}\sqrt{11}}=\dfrac{11\sqrt{11}-7\sqrt{5}\sqrt{11}}{3\times11}\\\\=\dfrac{11\sqrt{11}-7\sqrt{55}}{33}[/tex]
