Question

if a=9-4√5 , then find the value of a-1/a

Answer 1

In this question,

a=9-4root5

For 1/a we have to rationalise the denominators

so the result after rationalising = 9+4root5

a-1/a = 9-4root5 -(9+4root5)

= -4root5 -4root5

= -8root5.

Be Brainly.