SOLUTION: what type of stationery points does the function y= 12x-3x^2-9 have and what is the value of y at that point?

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Question 1052724: what type of stationery points does the function y= 12x-3x^2-9 have and what is the value of y at that point?
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The function is y=-3x^2+12x-9
The derivative is -6x+12
set that equal to 0
-6x+12=0
6x=12
x=2
At x=2 the function has a rate of instantaneous change of 0.
It is positive, so this is a local maximum.
The value of y is 3
The vertex x-value is at -b/2a or -12/-6=2 as a check
f(2)=-12+24-9=3.
graph%28300%2C300%2C-10%2C10%2C-10%2C10%2C-3x%5E2%2B12x-9%29