x / y = √2 / √3 schimbam proportia in x / √2 = y / √3 = k
x = √2k
y = √3k
( x + y ) / ( y - x ) = ( √2k +√3k ) / ( √3k - √2k ) =
= ( √2 + √3) ·k / ( √3 - √2) ·k = ( √3 + √2) / ( √3 - √2) =
= ( √3 + √2) ² / ( √3 - √2) · (√3 + √2) =
= (√3 +√2)² / 1 = 3 + 2√6 +2 = 5 +2√6
