单选题
Points (-2, x)and(y, 2), not shown in the figure above, are in quadrants Ⅲ and Ⅱ, respectively, in which quadrant is point(x, y)?
【正确答案】
C
【答案解析】(-2,x)在第三象限,那么x就绝对不可能为0,x必然小于0;同样道理,(y,2)在第二象限,那么y必然小于0,所以(x,y)一定在第三象限。正确答案为C。坐标系中任意两点间的距离:P2P1=

连接任意两点的线段的中点坐标:(xm,ym)=
