The ordinate intersecting with the Y axis is the value of C, because Y = AX 2+BX+C. When x=0 and y=c=8, the coordinates of the two generation points A and B can be obtained. For example, (5,6) and (15,3) are 6 = 5 2× A+. 3 = 15 2× A+ 15B+8, the solution is a =1195, and b=- 10/39.