问题描述: (3m-4n)^2+2(3m-4n)(3m+4n)-3(3m+4n)^2 1个回答 分类:综合 2014-10-05 问题解答: 我来补答 (3m-4n)^2+2(3m-4n)(3m+4n)-3(3m+4n)^2=9m^2-24mn+16n^3+18m^2-32n^2-27m^2-72mn-48n^2=-96mn-64n^2=-96*(-2)*1/4-64*(1/4)^2=48-4=44 展开全文阅读