(x^2+2xy+y^2-4xy)*(x^2-2xy+y^2+4xy)
问题描述:
(x^2+2xy+y^2-4xy)*(x^2-2xy+y^2+4xy)
答
x^2+2xy+y^2-4xy=x^2-2xy+y^2=(x-y)^2
x^2-2xy+y^2+4xy=x^2+2xy+y^2=(x+y)^2
原式= [(x-y)(x+y)]^2 =(x^2-y^2)^2 = x四次方 - 2x^2y^2 + 主y 四次方.