x^4+4y^4(因式分解)

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

用添项法!

x^4+4y^4
=x^4+4X^2y^2+4y^4-4x^2y^2
=(x^2+2y^2)^2-(2xy)
=(x^2+2y^2+2xy)(x^2+2y^2-2xy)

x^4+4y^4=(x^2+2y^2)^2-4x^2y^2=(x^2+2y^2+2xy)(x^2+2y^2-2xy)
已经有人比我快了!!

(X^2)^2+(2Y)^2

同学，这不能分……

也没看懂你的题啊‘'