1、原式=-4a^5b^10c^3
2、原式=4a^2+4ay+y^2-y^2-4xy
=4a^2+4ay-4xy
3、原式=x^2+3xy-8xy-12y^2-x^2+xy-2xy+2y^2
=-10y^2-6xy
计算4a^4b^7c·(-ab³c²)
1、原式=-4a^5b^10c^3
2、原式=4a^2+4ay+y^2-y^2-4xy
=4a^2+4ay-4xy
3、原式=x^2+3xy-8xy-12y^2-x^2+xy-2xy+2y^2
=-10y^2-6xy