Contact us
Choose a category below so we can get back to you as quickly as possible.
由題意得,x-1=0,y-2=0,解得x=1,y=2,所以,x-y=1-2=-1.故選D.
We and our partners use cookies and other technologies to analyze traffic and optimize your experience. View more info and control your cookies settings at any time in our Cookies Policy.