方程|x-2y-3|+|x+y+1|=1的整数解的个数是:2个分四种情况讨论：①x-2y-3=0,x+y+1=1解得x=1,y=-1②x-2y-3=0,x+y+1=-1解得x=-1/3,y=-5/3③x-2y-3=1,x+y+1=0解得x=0,y=-1④x-2y-3=-1,x+y+1=0解得x=2/3,y=-5/3得上述4个方...