SOLUTION: Hello, I have to write the transformational form equation of a parabola that opens up or down and passes through (3,12), (5,28), and (4,18). Help?

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: Hello, I have to write the transformational form equation of a parabola that opens up or down and passes through (3,12), (5,28), and (4,18). Help?      Log On


   

Question 948030: Hello, I have to write the transformational form equation of a parabola that opens up or down and passes through (3,12), (5,28), and (4,18). Help?
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Hello, I have to write the transformational form equation of a parabola that opens up or down and passes through (3,12), (5,28), and (4,18). Help?
============
ax^2 + bx + c = y
Using (3,12) :: 9a + 3b + c = 12
Using (5,28) :: 25a + 5b + c = 28
Using (4,18) :: 16a + 4b + c = 18
-------
Using my TI- 84 Matrix Program I get:
a = 2
b = -8
c = 18
----
Equation:
y = 2x^2 - 8x + 18
-----------------------
Cheers,
Stan H.