SOLUTION: What is the maximum point of the function {{{ f(x)=-3x^2+24x-30 }}}?

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Question 292007: What is the maximum point of the function +f%28x%29=-3x%5E2%2B24x-30+?

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
What is the maximum point of the function +f%28x%29=-3x%5E2%2B24x-30+?
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Since the given equation is a parabola that opens downward (we know this from the coefficient associated with the x^2 term -- if it is negative it opens downward -- if it is positive it opens upward). The vertex will give you the maximum.
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There are a few ways to find the vertex.
One way is to find the "axis of symmetry":
x = -b/2a = -24/(2(-3)) = -24/-6 = 4
That's the x-coordinate.
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To find the y-coordinate, plug it in back to the original function:
f(x)=-3x^2+24x-30
f(4)=-3(4)^2+24(4)-30
f(4)=-48+96-30
f(4)=18
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Maximum point is at (4,18)