I just need to know, how to find equation of a parabola and put it in the form ofax^2+bx+cjust from reading of the graph.

I can do this for graphs like these were it cuts the x-axis:

http://img141.imageshack.us/img141/7839/surf006lm9.jpg

but for graphs were itdoesn'tcut the x-axis:

http://img141.imageshack.us/img141/2050/surf007hz9.jpg

how would you find the equation?

Thanks