已知正實數x、y、z滿足x+y+xy=8y+z+yz=15z+x+zx=35,則x+y+z+xyz=______.

已知正實數x、y、z滿足x+y+xy=8y+z+yz=15z+x+zx=35,則x+y+z+xyz=______.

∵x+y+xy=8,∴x+y+xy+1=8+1,∴(x+1)(y+1)=9,同理可得:(y+1)(z+1)=16,(x+1)(z+1)=36,解得x=72,y=1,z=7.∴x+y+z+xyz=72+1+7+72×1×7=36.故填36.