分解因式：25（x+y)平方-16(x-y)平方

分类: 作业答案 • 2021-12-20 04:45:09

问题描述：

答

平方差，分为（9x+y)(x+9y)=0

答

[5(x+y)+4(x-y)][5(x+y)-4(x-y)]
=(9x+y)(x+9y)

答

=[5(x＋y)]²－[4(x－y)]²
=(5x＋5y＋4x－4y)(5x＋5y－4x＋4y)
=(9x＋y)(x＋9y)

答

25(x+y)²-16(x-y)²
=[5(x+y)]²-[4(x-y)]²
=[5(x+y)+4(x-y)][5(x+y)-4(x-y)]
=(9x+y)(x+9y)