计算(2x-3y-1)(-2x-3y+5)

来源:学生作业帮助网 编辑:作业帮 时间:2024/04/29 11:41:21
计算(2x-3y-1)(-2x-3y+5)

计算(2x-3y-1)(-2x-3y+5)
计算(2x-3y-1)(-2x-3y+5)

计算(2x-3y-1)(-2x-3y+5)
(2x-3y-1)(-2x-3y+5)
=【-2x(2x-3y-1)】+【-3y(2x-3y-1)】+【5(2x-3y-1)】
=【-4x²+6xy+2x】+【-6xy+9y²+3y】+【10x-15y-5】
=-4x²+6xy+2x-6xy+9y²+3y+10x-15y-5
=-4x²+12x+9y²-12y-5
=-4x²+9y²+12(x-y)-5

=-4x²-6xy+10x+6xy+9y²-15y+2x+3y-5
=-4x²+12x-12y+9y²-5

(2x-3y-1)(-2x-3y+5)
=-(2x-3y-1)(2x+3y-5)
=-[(2x-3y)(2x+3y)-5(2x-3y)-(2x+3y)+5]
=-[4x^2-9y^2-10x+15y-2x-3y+5]
=-[4x^2-9y^2-12x+12y+5]
=-4x^2+9y^2+12x-12y-5