Question

If a=9 - 4 under root 5, find the value of (a-1/ a)power 2
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Answer 1

Answer:

Step-by-step explanation:

a=9-4root5

1/a=1/9-4root5

rationalize it

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

    =9+4root5

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

       =18

(a+1/a)^2=18^2=324