SOLUTION: f(x)=-x^2+4x-9 Find the vertex What is the extremum value of the function?

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: f(x)=-x^2+4x-9 Find the vertex What is the extremum value of the function?      Log On


   

Question 114519: f(x)=-x^2+4x-9
Find the vertex
What is the extremum value of the function?
Answer by HyperBrain(694) About Me  (Show Source):
You can put this solution on YOUR website!
Please read my lesson---Shortcut in finding the vertex of any parabola
IF y=-x%5E2%2B4x-9, then dy%2F%28dx%29=-2x%2B4

Equating to zero,
-2x%2B4=0
-2x=-4
x=1%2F2
Solving for y,
y=-%281%2F2%29%5E2%2B4%281%2F2%29-9=-31%2F4

Thus, the vertex is at (1%2F2%29,-31%2F4)

Power up,\
HyperBrain!