Split - Quadratic Help - equation of parabola

[lizzygirl223]

three points on a parabola are given below. Using an algebraic method, write the equation of the function.
(-1,5), (0,3), (3,9)

 

[Deleted member 4993]

three points on a parabola are given below. Using an algebraic method, write the equation of the function.
(-1,5), (0,3), (3,9)

General equation of a parabola is:

y = ax[sup:204yiub9]2[/sup:204yiub9] + bx + c

using three given points we write:

5 = a - b + c

3 = 0 a + 0 b + c

9 = 9a + 3b + c

You have 3 equations and three unknowns.

Please show us your work, indicating exactly where you are stuck - so that we may know where to begin to help you.