writing quadratic equation for a graph

[Motherof8]

Write a quadratic function that fits each set of points: (-1,-11), (1,0) (2,9). I plotted these points on a graph but I cannot find a common equation that would fit all these points. Would appreciate advice that would help solve this problem. Thank you.

[maggiemagnet]

Write a quadratic function that fits each set of points: (-1,-11), (1,0) (2,9). I plotted these points on a graph but I cannot find a common equation that would fit all these points. Would appreciate advice that would help solve this problem. Thank you.

There's an example of this exact same kind of thing here.

Your system of equations will be:

a - b + c = -11
a + b + c = 0
4a + 2b + c = 9