问题描述: 若x+y=10,x3+y3=100,则x2+y2=______. 1个回答 分类:数学 2014-11-23 问题解答: 我来补答 x3+y3=(x+y)(x2-xy+y2),∴x2-xy+y2=10,∵x+y=10,∴x2+2xy+y2=100,∴2xy=100-(x2+y2),把xy=x2+y2-10,代入得:100-(x2+y2)=2(x2+y2-10)=2(x2+y2)-20,3(x2+y2)=120,∴x2+y2=40.故答案为:40. 展开全文阅读