(3m-4n)^2+2(3m-4n)(3m+4n)-3(3m+4n)^2

分类: 作业答案 • 2021-12-31 22:55:08

问题描述：

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