(x+y)^3+2xy-2x^2y-2xy^2-1
=(x+y)^3-1+2xy-2xy(x+y)+2xy-1
=(x+y-1)[(x+y)²+(x+y)+1]-2xy(x+y-1)
=(x+y-1)(x²+2xy+y²+x+y+1-2xy)
=(x+y-1)(x²+y²+x+y+1)貌似..错了吧..(x+y)^3+2xy-2x^2y-2xy^2-1==(x+y)^3-1+2xy-2xy(x+y)+2xy-1吗?多写了一个2xy-1，是抄错的(x+y)^3+2xy-2x^2y-2xy^2-1=(x+y)^3-1+2xy-2xy(x+y)=(x+y-1)[(x+y)²+(x+y)+1]-2xy(x+y-1)=(x+y-1)(x²+2xy+y²+x+y+1-2xy)=(x+y-1)(x²+y²+x+y+1)