1.x^4+4 =x^4+4x^2+4-4x^2=(x^2+2)^2-(2x)^2=(x^2+2+2x)(x^2+2-2x)2.x^4+y^4+(x+y)^4=x^4+y^4+(x^2+y^2+2xy)^2=(x^2+y^2)^2-2x^2y^2+(x^2+y^2)^2+4xy(x^2+y^2)+4x^2y^2=2[(x^2+y^2)^2+2xy(x^2+y^2)+（xy)^2]=2（x^2+...第2的答案请详细点 我水平较低... 第三的答案是（x+y+z)(x+y-z)(x-y+z)(y+z-x) 你再试试2. x^4+y^4+(x+y)^4=x^4+y^4+【(x^2+y^2）+2xy】^2=(x^2+y^2)^2-2x^2y^2+(x^2+y^2)^2+4xy(x^2+y^2)+4x^2y^2=2(x^2+y^2)^2+2x^2y^2+4xy(x^2+y^2)=2[(x^2+y^2)^2+2xy(x^2+y^2)+（xy)^2]=2（x^2+y^2+xy)^23,4x^2y^2-x^4-y^4-z^4-2(x^2y^2-y^2z^2-z^2x*2) =-[(x²-y²)²-2x²y²+z^4+2x²y²-2y²z²-2z²x²]=-[(x²-y²)²+z^4-y²z²-z²x²+2xyz²-2xyz²-y²z²-z²x²]=-[(x²-y²)²+z^4-z²(x-y)²-z²(x+y)²]=-{（x+y)²(x-y)²-z²[(x-y)²+(x+y)²]+z^4}=-[(x+y)²-z²][(x-y)²-z²]（x+y)²╲ -z² 十字相乘=-(x+y+z)(x+y-z)(x-y+z)(x-y-z)(x-y)² ╱ -z²=(x^2+y^2)^2-2x^2y^2+(x^2+y^2)^2+4xy(x^2+y^2)+4x^2y^2怎么来的？x^4+y^4 【(x^2+y^2）+2xy】^2=x^4+y^4+2x^2y^2-2x^2y^2=(x^2+y^2)^2-2x^2y^2 =(x^2+y^2)^2+4xy(x^2+y^2)+4x^2y^2给你分开了！输入好麻烦的