因式分解(x+y)^2-(x-y)^2=

问题描述:

因式分解(x+y)^2-(x-y)^2=

慢了

(x+y)²-(x-y)²
=(x+y+x-y)(x+y-x+y)
=2x×2y
=4xy

使用平方差公式
 
原式
=【(x+y)+(x-y)】【(x+y)-(x-y)】
=2x乘以2y
=4xy
 

(x+y+x-y)(x+y-x+y)
=2x×2y
=4xy