Answer:
[tex]\frac{\sqrt{7} +2\sqrt{5}}{\sqrt{7}-\sqrt{5} }\\\\=\frac{\sqrt{7} +2\sqrt{5}}{\sqrt{7}-\sqrt{5} }*\frac{\sqrt{7} +\sqrt{5}}{\sqrt{7}+\sqrt{5} }\\\\ =\frac{(\sqrt{7} +2\sqrt{5})(\sqrt{7} + \sqrt{5} )}{(\sqrt{7}-\sqrt{5})(\sqrt{7}+\sqrt{5})\\ }\\\\=\frac{17 +3\sqrt{35} }{2}[/tex]
