已知A=3a^2b-ab^2,B=ab^2-3a^b①求5A-B②求2A-3B ※※※※※※※※※※※※※※※※※※※※※※※要过程

问题描述:

已知A=3a^2b-ab^2,B=ab^2-3a^b①求5A-B②求2A-3B ※※※※※※※※※※※※※※※※※※※※※※※要过程

A=3a²b-ab²,B=ab²-3a²b5A-B=5(3a²b-ab²)-(ab²-3a²b)=(15+3)a²b-(5+1)ab²=18a²b-6ab²=6ab(a-b)2A-3B=2(3a²b-ab²)-3(ab²-3a²b)...