(xyz²+4xy-1)+(-3xy+z²xy-3)-(2xy²+xy)
=xyz²+4xy-1-3xy+xyz²-3-2xy²-xy
=2xyz²-2xy²-4
因此选D
如果换成:
(xyz²+4xy-1)+(-3xy+z²xy-3)-(2xyz²+xy)
=-4
选A
(xyz²+4xy-1)+(-3xy+z²xy-3)-(2xy²+xy)
=xyz²+4xy-1-3xy+xyz²-3-2xy²-xy
=2xyz²-2xy²-4
因此选D
如果换成:
(xyz²+4xy-1)+(-3xy+z²xy-3)-(2xyz²+xy)
=-4
选A