Question

If x=9-4√5, then (x+1/x)​

Answer 1

x= (9-4√5)

so,

1/x = 1/(9-4√5)

= (9+4√5)/(81-80)

= (9+4√5)/1

now ,

(x+1/x)

= {(9-4√5)+(9+4√5)}

= 18