So the axis of symmetry is on the right of point p.
Parabola should be an axisymmetric figure.
P(- 1,2b),BP=2PA。
So B(-3, -2b) -b- 1\2=-2.
So b=5.
There should be b+c=-2, so c=-7.
So the quadratic function relation corresponding to parabola is y=x2+4x-7.
Gee, I'm very tired. Plus points ~ ~
Hu roared ~