因为x-y=5,xy=6
那么x²y-xy²=xy(x-y)=6*5=30
x²+y²=(x-y)²+2xy=5²+2*6=37
如果不懂,祝学习愉快!写错一个x^2y+xy^2=,(x+y)²=x²+y²+2xy=37+2*6=49所以x+y=±7所以x²y+xy²=xy(x+y)=6*(±7)=±42