在2-【2(x+y)-()】=x+2,括号内应填

问题描述:

在2-【2(x+y)-()】=x+2,括号内应填

2-【2(x+y)-()】=x+2
-【2(x+y)-()】=x
【2(x+y)-()】=-x
2(x+y)-()=-x
2(x+y)=-x+()
()=2(x+y)+x
()=2x+2y+x
()=3x+2y