根据题意得x+y-5=0xy-3=0∴x+y=5xy=3∴x²+y²=(x+y)²-2xy=25-6=19x²-y²=(x+y)(x-y)∵(x-y)²=(x+y)²-4xy=25-12=13∴x-y=±√13∴x²-y²=±5√13