网络工程师考证多少钱:已知AB=2,A-B=-3,求(-2AB-3B)+3A-5(AB+B-A)的直

来源:百度文库 编辑:高校问答 时间:2024/04/29 22:10:08
我要过程和思路

(-2AB-3B)+3A-5(AB+B-A)
=-2AB-3B+3A-5AB-5B+5A
=-2AB+3(A-B)-5AB+5(A-B)
=-2*2+3*(-3)-5*2+5*(-3)
=-4-9-10-15
=-38

=-2*2+3*(-3)-5*[2-(-3)]
=-38

答案是-38
原式整理=-7AB+8(A-B)=-7*2+8*(-3)

-38

(-2AB-3B)+3A-5(AB+B-A)
=-2AB-3B+3A-5AB-5B+5A
=-2AB+3(A-B)-5AB+5(A-B)
=-2*2+3*(-3)-5*2+5*(-3)
=-4-9-10-15
=-38