# Math Help - Finding equation of parabola passing through three known points.

1. ## Finding equation of parabola passing through three known points.

Find the equation of a parabola that passes through the points (-2,3), (-1,1) and (1,9). Any help would be great;so confused right now. Stuck on this for over a hour now!

2. Well the equation of a parabola is $y = ax^2+bx+c$

substitute your points in one at a time then solve remaining system of equations.

Here's a kicker.

$(-2,3): 3 = a(-2)^2+b(-2)+c \implies 3 = 4a-2b+c$

Now you have a go.

3. okay ill try some more now. ty

4. If you substitute the values into the general quadratic equation, then you get a linear system, which you can solve with substitution methodes.