化简求值：(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y),其中x=2,y=-1在线急等

分类: 作业答案 • 2021-12-19 16:39:37

问题描述：

化简求值：(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y),其中x=2,y=-1
在线急等

答

(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y)
=(24+2)(6+2-1)-(8-3)(18-6)
=26*7-5*12
=182-60
=122

答

(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y)
=21x^2-14xy-7x-6xy+4y^2+2y-36x^2-24xy-27xy-18y^2
=-15x^2-70xy-7x-14y^2+2y
=-60+140-14-14-2
=50