Question

1 upon 5 + 3 root 2​

Answer 1

$\frac{1}{5 + 3 \sqrt{2} } \\ = \frac{1}{5 + 3 \sqrt{2} } \times \frac{5 - 3 \sqrt{2} }{5 - 3 \sqrt{2} } \\ = \frac{5 - 3 \sqrt{2} }{ {5}^{2} - {3 \sqrt{2} }^{2} } \\ = \frac{5 - 3 \sqrt{2} }{25 - 18} \\ = \frac{5 - 3 \sqrt{2} }{7}$