已知x-y=3,xy = -2,求代数式(2x=3y-2xy)-(x+4y+xy)-(3xy+2y-2x-3)的值
问题描述:
已知x-y=3,xy = -2,求代数式(2x=3y-2xy)-(x+4y+xy)-(3xy+2y-2x-3)的值
答
题有问题(2x=3y-2xy)怎么会是2X=?原题:(2x+3y-2xy)-(x+4y+xy)-(3xy+2y-2x-3)(2x+3y-2xy)-(x+4y+xy)-(3xy+2y-2x-3)=2x+3y-2xy-x-4y-xy-(3xy+2y-2x-3)=x-y-3xy-(3xy+2y-2x-3)=(x-y)-3xy-【3xy-2(x-y)-3】=...