x²-4y²+x-2y
=(x^2-4y^2)+(x-2y)
=(x+2y)(x-2y)+(x-2y)
=(x-2y)(x+2y+1)
是a^3+a^2b-ab^2-b^3吧
=(a^3+a^2b)-(ab^2+b^3)
=a^2(a+b)-b^2(a+b)
=(a^2-b^2)(a+b)
=(a+b)^2(a-b)