题:(2x-y-3)的平方 （要求写出计算过程）
问题描述：
题:(2x-y-3)的平方 （要求写出计算过程）
答
(2x-y-3)^2
=[2x-(y+3)]^2
=4x^2-4x(y+3)+(y+3)^2
=4x^2-4xy-12x+y^2+6y+9
答
=[2x-(y+3)]^2
=4x^2-4x(y+3)+(y+3)^2
=4x^2-4xy-12x+y^2+6y+9
答
(2x-y-3)^2
=(2x-y-3)(2x-y-3)
=4x^2-2xy-6x-2xy+y^2+3y-6x+3y+9
=4x^2-4xy-12x+6y+y^2+9