x4次方y4次方-8x2次方y2次方+16

问题描述:

x4次方y4次方-8x2次方y2次方+16

x4次方y4次方-8x2次方y2次方+16
=x^4y^4-8x^2y^2+16
=(x^2y^2-4)^2
=(xy+2)^2(xy-2)^2