Question

If x=9+4√5 , find x^2+1/x^2

Answer 1

(9+4√5)²+1/(9+4√5)²

=81+36√5+36√5+80+1/81+36√5+36√5+80

=72√5+162/72√5+161

Answer 2

HEY MATE HERE IS YOUR ANSWER--

X=9+4√5

PUTTING VALUE OF X

$({9 + 4 \sqrt{5} })^{2} + \frac{1}{( {9 + 4 \sqrt{5} )}^{2} } \\ \\ 845 + \frac{1}{845} \\ \\ take \: lcm \: \\ \\ \frac{845}{1} + \frac{1}{845} \\ \\ \frac{714025 +845 }{845} \\ \\ \frac{714870}{845} = 846$

=>846 answer