问题描述: 若m-n=4,mn=-1,求代数式(9-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)的值 1个回答 分类:数学 2014-12-12 问题解答: 我来补答 (9-2mn+2m+3n)-(3mn+2n-2m)-(m+4n+mn)=9-2mn+2m+3n- 3mn-2n+2m-m-4n-mn=9-6mn+3m-3n=9-6mn+3(m-n)=9-6×(-1)+3×4=9+6+12=27 展开全文阅读