SOLUTION: How do I find the vertex of the following parabola f(x)= -x^2 + 9x -5

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Question 81128: How do I find the vertex of the following parabola
f(x)= -x^2 + 9x -5
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
the vertex is on the axis of symmetry; the general equation of which is x=-b/2a ... in this case, x=-9/(-2), or x=4.5

so the x value for the vertex is 4.5 ... to find the y value, just substitute into the equation

y=-%284.5%5E2%29%2B9%284.5%29-5 ... so y=15.25 ... vertex is (4.5,15.25)