If x = ?3 + 1/ ?3 - 1 and y = ?3 - 1/ ?3 + 1, then x² + y² is equal to

You can square the both the equation and add them to find the answer.

x² + y² = ( (?3 + 1 ) / ( ?3 - 1 ) )² + ( (?3 - 1 ) / (?3 + 1) )²
x² + y² = ( ?3 + 1 )² / ( ?3 - 1 ) ² + (?3 - 1 )² / (?3 + 1) ²
x² + y² = ( ( 3 + 1 + 2 ?3 ) / ( 3 + 1 - 2 ?3 ) ) + ( ( 3 + 1 - 2?3) / ( 3 + 1 + 2 ?3 ) )
x² + y² = ( 4 + 2 ?3 ) / ( 4 - 2 ?3 ) + ( 4 - 2?3 ) / ( 4 + 2 ?3 )
x² + y² = ( 2 + ?3 ) / ( 2 - ?3 ) + ( 2 - ?3 ) / ( 2 + ?3 )
x² + y² = (4 + 3 + 4 ?3 + 4 + 3 - 4 ?3) / ( 4 - 3 )
x² + y² = 14