(x+y²)+9(x-y)²-6(x²-y²)

分类: 作业答案 • 2022-01-30 13:05:06

问题描述：

答

(x+y)²+9(x-y)²-6(x²-y²)=(x+y)²-2·(x+y)·[3(x-y)]+[3(x-y)]²=[(x+y)-3(x-y)]²=(x+y-3x+3y)²=(-2x+4y)²=4(x-2y)²