A:3.3×1025
B:3.3×1024
C:7.5×1023
D:7.5×1022
Where's Sam's dictionary?
如图,已知一动圆的圆心P在抛物线y= 12 x2﹣3x+3上运动.若⊙P半径为1,点P的坐标为(m,n),当⊙P与x轴相交时,点P的横坐标m的取值范围是____.