(x²十x)²一(x十1)²
=[(x²+x)+(x+1)][(x²+x)-(x+1)]
=(x²+x+x+1)(x²+x-x-1)
=(x²+2x+1)(x²-1)
=(x+1)²(x+1)(x-1)
=(x+1)²(x-1）