1、(x+y)乘(x-y)的三次方+(x+y)的三次方乘(y-x)
=（x+y)(x-y)((x-y)²-(x+y)²)
=（x+y)(x-y)(x-y+x+y)(x-y-x-y)
=-4xy(x+y)(x-y)
2、64x的5次方乘y的5次方-xy
=xy(64x^4y^4-1)
=xy(8x²y²+1)(8x²y²-1)
3、36乘（2x-y)的三次方+9乘(y-2x)
=36（2x-y)³-9(2x-y)
=9(2x-y)(4(2x-y)²-1)
=9(2x-y)(2(2x-y)+1)(2(2x-y)-1)
=9(2x-y)(4x-2y+1)(4x-2y-1）
4、8分之一x的两次方乘y的四次方-2分之1x的四次方乘y的两次方
=x²y^4/8-x^4y²/2
=(x²y²/8)(y²-4x²)
=(x²y²/8)(y+2x)(y-2x)