x+y+5=xy≤(x+y)²/4
(x+y)²-4(x+y)-20≥0
(x+y-2)²≥24
x+y≥2+2√6
3xy=x+y+5≥2√(xy)+5
3xy-2√(xy)-5≥0
(3√(xy)-5)(√(xy)+1)≥0
√(xy)≥5/3
xy≥25/9