3x3－3x2－y2＋5y+x2－5y＋y2 0.0 求亲们帮帮忙

3x3－3x2－y2＋5y+x2－5y＋y2
=3x3+(x2-3x2)+(y2－y2)＋(5y－5y)
=3x3-2x2

(4x2-4xy+y2)+(x2-2x+1)=0
(2x-y)2+(x-1)2=0
平方相加为0则都等于0
所以2x-y=0,x-1=0
x=1,y=2x=2
x-y=-1
所以（x-y）的2006次方=1