The equation for a parabola would be knowing the values of in .
What does C = (-2,7) on the parabola tell you? It says that when x = -2, the y value of that formula will be 7.
So C on the parabola tells you that .
A and B on the parabola will likewise tell you something. And if you know what a, b, and c are, then you have "found the parabola".