Question

help me to find the answer

Answer 1

Given  x = 9 - 4√5

$= > \frac{1}{x} = \frac{1}{9 - 4\sqrt{5}} * \frac{9 + 4\sqrt{5}}{9 + 4\sqrt{5}}$

$= > \frac{9 + 4\sqrt{5}}{(9)^2 - (4\sqrt{5})^2}$

$= > \frac{9 + 4\sqrt{5}}{81 - 80}$

$= > \frac{9 + 4\sqrt{5}}{1}$

$= > 9 + 4\sqrt{5}$

Now,

= > x + 1/x

= > 9 - 4√5 + 9 + 4√5

= > 18.

So, x + 1/x = 18

Now,

On squaring both sides, we get

= > (x + 1/x)^2 = (18)^2

= > x^2 + 1/x^2 + 2 = 324

= > x^2 + 1/x^2 = 322.

Hope it helps!

Answer 2

HOPE THIS WILL HELP U