Question

If a=9-4root 5 find the value of a-1/a whole square​

Answer 1

Answer:

a=9-4√5

1/a=1/(9-4√5)

=1*(9+4√5)/(9)2-(4√5)2

=(9+4√5)/81-80

=9+4√5

(a + 1/a)² - 2a(1/a)

= ( 9 - 4√5 + 9 + 4√5)² - 2

= 18² - 2

= 324 - 2

= 322

Step-by-step explanation: