Question

Efectuați calculele raționalizând numitorii:

Answer 1

$\frac{8}{2\sqrt{5}-4}+\frac{2\sqrt{5}}{\sqrt{5}+2}-\frac{4\sqrt{5}}{7-3\sqrt{5}} = \frac{8(2\sqrt{5}+4)}{4\cdot5-16}+\frac{2\sqrt{5}(\sqrt{5}-2)}{5-4}-\frac{4\sqrt{5}(7+3\sqrt{5})}{49-9\cdot5} = 4\sqrt{5}+8+10-4\sqrt{5}-7\sqrt{5}-15 = 3-7\sqrt{5}$