2x²y²-x的4次方-y的4次方=

2x²y²-x的4次方-y的4次方=
2x²y²-x的4次方-y的4次方=

2x²y²-x的4次方-y的4次方=
2x²y²-x的4次方-y的4次方
=-(x^4+y^4-2x^2y^2)
=-(x^2-y^2)^2
=-(x+y)^2(x-y)^2

解2x²y²-x的4次方-y的4次方
=-（-2x²y²+x的4次方+y的4次方）
=-（x的4次方-2x²y²+y的4次方）
=-（x²-y²）²

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

2x²y²-x的4次方-y的4次方
=（2x²y²-x)²+y²乘以(2x²y²-x)²-y²
你接着往下推吧