〔注:由于输入法问题,平方或立方等方均为：N^n〕(1)x^2（x-1）-y^2（y-1）(2)x^2-8xy+15y^2+2x-4y-3(3)x^4+x^2y^2+y^4(4)x^4+y^4+2^4-2x^2y^2-2x^22^2-2y^22^2(5)x^3+6x^2y+11xy^2+6y^3
问题描述：
〔注:由于输入法问题,平方或立方等方均为：N^n〕(1)x^2（x-1）-y^2（y-1）
(2)x^2-8xy+15y^2+2x-4y-3
(3)x^4+x^2y^2+y^4
(4)x^4+y^4+2^4-2x^2y^2-2x^22^2-2y^22^2
(5)x^3+6x^2y+11xy^2+6y^3
答
(1)原式=x^3-x^2-y^3+y^2
=(x^3-y^3)+(x^2-y^2)
=(x-y)(x^2+xy+y^2)+(x-y)(x+y)
=(x-y)(x^2+xy+y^2+x+y)