Question

hey everyone i m new here
plzz help me with question no. 13​

Answer 1

REFER TO THE ATTACHMENT ❤️

Answer 2

$x = 9 - 4 \sqrt{5} \\ \\ {x}^{2} = {9}^{2} - 2(9)(4 \sqrt{5} ) + {(4 \sqrt{5} )}^{2} \\ \\ {x}^{2} = 161 - 72 \sqrt{5} \\ \\ \frac{1}{x} = \frac{1}{9 - 4 \sqrt{5} } \\ \\ \frac{1}{x} = \frac{1}{(9 - 4 \sqrt{5} )} \frac{(9 + 4 \sqrt{5} )}{(9 + 4 \sqrt{5} ) } \\ \\ \frac{1}{x} = 9 + 4 \sqrt{5} \\ \\ \frac{1}{ {x}^{2} } = 161 + 72 \sqrt{5} \\ \\ {x}^{2} + \frac{1}{ {x}^{2} } = 322$

hope it helps