what is the maximum value of the function? y=-3x2+12x-8

Question

Standard form quadratic equation.

Answer 1

Hello, thank you for taking the time to post your question!

Since it’s a parabola that opens downward (negative first coefficient), that means that the maximum value is going to occur at the vertex.

So you can find x = -b/2a = -12 / 2(-3) = -12 / -6 = 2 , meaning that the x coordinate of the maximum value is “2”

To find the actual maximum value then you want to plug x = 2 back into the original function

y = -3(2)^2 + 12(2) – 8

y = -3(4) + 24 – 8

y = -12 + 24 – 8

y = 12 – 8

y = 4

so the maximum value of the function here is 4

I hope that helps you get moving in a better direction on this type of question! Feel free to reach out if you have any additional questions beyond that :)

Answer 2

Hi Ruth;

y=-3x²+12x-8

It is a parabola which opens downward.

The maximum position is the vertex...

x=-b/2a

x=-12/2(-3)

x=-12/-6=2

y=-3(2²)+12(2)-8

y=-3(4)+24-8

y=-12+24-8

y=4

 

SORRY FOR THE MISTAKE.