Experts, Meritnation

I am unable to solve one of the questions of my Olympiad book. This was the question:

I f   '' x   =   3   -   1 '' ,   t h e n   f i n d   t h e   v a l u e   o f   x + 1 x 2


Please help me to solve this. When I saw the answer key in the Olympiad book, the answer shown was   7 - 3 3 2 , but solution was not given in the book.   

Dear student
Given: x=3-1 ...1To find: x+1x2Consider , 1x=13-1×3+13+1   On rationalising =3+132-12  using  a2-b2=a+ba-b=3+13-1=3+12  ..2Adding 1 and 2 we getx+1x=3-1+32+12   using 1 and 2=332-12=33-12So, x+1x2=33-122=27+1-634    using a-b2=a2+b2-2ab=28-634=7-332
Regards

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