Question

if a=9-4 root 5 find the value of (a-1/a square​

Answer 1

Answer:

Given,

a= 9-4√5

So, a-1/a

= a^2 - 1/a

= (9-4√5)^2 - 1(9+4√5)/(9-4√5)(9+4√5)

= 81 - 80 - 9 - 4√5/(9)^2 - (4√5)^2

= -8 - 4√5/ 81 - 80

= -8 -4√5

Answer 2

correct answer is 322

i hope it helped you