SOLUTION: Find the maximum or minimum value of the function. f(x)= -x^2/3+2x+6 (it's -x^2 over 3 then +2x+6) I thought that you have to use -b/2a and then f(x)=-b/2a

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: Find the maximum or minimum value of the function. f(x)= -x^2/3+2x+6 (it's -x^2 over 3 then +2x+6) I thought that you have to use -b/2a and then f(x)=-b/2a       Log On


   

Question 411199: Find the maximum or minimum value of the function.
f(x)= -x^2/3+2x+6 (it's -x^2 over 3 then +2x+6)

I thought that you have to use -b/2a and then f(x)=-b/2a

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
Find the maximum or minimum value of the function.
f(x)= -x^2/3+2x+6 (it's -x^2 over 3 then +2x+6)
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a = (-1/3) ; b = 2 ; c = 6
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I thought that you have to use -b/2a and then f(x)=-b/2a
Max or min occurs at x = -b/(2a) = -2/(2*(-1/3)) = -2/(-2/3) = 3
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f(3) = (-1/3)(3^2) + 2(3) + 6
= -3+6+6
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= 9
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Cheers,
Stan H.
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