已知x,y均為正實數,且xy=x+y+3,則xy的最小值為______.

已知x,y均為正實數,且xy=x+y+3,則xy的最小值為______.

∵x,y均為正實數,且xy=x+y+3∴xy=x+y+3≥2xy+3 ; ;(當x=y時取等號)即(xy)2-2xy-3≥0∴(xy+1)(xy-3)≥0∵x,y均為正實數∴xy+1>0∴xy-3≥0 ;即xy≥9故xy的最小值為9.