Question

Racionalize os denominadores 9/9+√5

Answer 1

$\frac{9}{9 + \sqrt{5}} \times \frac{9 - \sqrt{5}}{9 - \sqrt{5}} = \frac{9 (9 - \sqrt{5})}{(9 + \sqrt{5})(9 - \sqrt{5})} = \frac{81 - 9\sqrt{5}}{9^2 - \sqrt{5}^2} = \frac{81 - 9\sqrt{5}}{81 - 5} = \frac{81 - 9\sqrt{5}}{76}$