已知x+y+2(-x-y+1)=3(1-y-z)-4(y+x-1),则x+y的值是

已知x+y+2(-x-y+1)=3(1-y-z)-4(y+x-1),则x+y的值是
已知x+y+2(-x-y+1)=3(1-y-z)-4(y+x-1),则x+y的值是

已知x+y+2(-x-y+1)=3(1-y-z)-4(y+x-1),则x+y的值是
后面怎么冒出来Z的?应该是X吧?
如果后面z改成x的话,答案应该是3/2.