因式分解(x³+y³)²-9x²y²(x+y)²

问题描述:

因式分解(x³+y³)²-9x²y²(x+y)²

原式=(x³+y³)²-[3xy(x+y)]²=[(x³+y³)+3xy(x+y)][(x³+y³)-3xy(x+y)]=[(x+y)(x²-xy+y²)+3xy(x+y)][(x+y)(x²-xy+y²)-3xy(x+y)]=(x+y)(x²-xy+y²...您的回答很好,但是从(x³+y³)²-[3xy(x+y)]²是如何变成[(x³+y³)+3xy(x+y)][(x³+y³)-3xy(x+y)]的呢这是平方差公式a^2-b^2=(a+b)(a-b)