SOLUTION: For the quadratic function, write the equation of the axis of symmetry, and find the coordinates of the vertex. y=9xsquared-54x+78

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Question 1034982: For the quadratic function, write the equation of the axis of symmetry, and find the coordinates of the vertex. y=9xsquared-54x+78
Found 2 solutions by fractalier, Cromlix:
Answer by fractalier(6550) (Show Source):
You can put this solution on YOUR website!
For

we can find the coordinates of the vertex via
(,)
Here a = 9, b = -54, so that
-b/2a = 54/18 = 3
f(3) = 9*3^2 - 54(3) + 78 = 81 - 162 + 78 = -3
Thus the vertex is at (3, -3) and the line of symmetry is vertical thru that, at x = 3.

Answer by Cromlix(4381) (Show Source):
You can put this solution on YOUR website!
Hi there,
y = 9x^2 - 54x + 78
a = 9, b = -54, c = 78
Vertex = -b/2a
Vertex = 54/18 = 3
x = 3
This is the axis of symmetry.
x = 3
Substitute in:-
y = 9x^2 - 54x + 78
y = 9(3)^2 - 54(3) + 78
y = -3
Vertex (3,-3)
Hope this helps :-)