Quadratic Functions

Need help for a quiz. How do i find the minimum or maximum value of a function?

for example a function like
f(x)= x² + 2x - 35
I know that the function has a minimum value because the a value is positive but how do i find what the minimum value is?

ᕼᗷ said:

Need help for a quiz. How do i find the minimum or maximum value of a function?

for example a function like
f(x)= x² + 2x - 35
I know that the function has a minimum value because the a value is positive but how do i find what the minimum value is?

Click to expand...

the local minimum or max, or just where the vertex is? Because if the fuction is positive then it has a MAXIMUM not a minimum value, and the maximum is the vertex which you can find by putting into vertex form.

Vertex Form:
f(x)=x^2+2x-35
f(x)=(x^2+2x) - 35
f(x)=(x^2+2x+1) -35-1
f(x)=(x+1)^2-36
So I believe the maximum value is (-1,36)

you use x= -b/2a (a and b being the coefficients of x) and then plug that into the original equation for the x. the minimum would be (the solution to -b/2a, answer when solution is plugged in for x).

if that's confusing my kik is Heist you can message me there

remember, if A is positive the graph looks like a happy face (minimum value), and if A is negative it makes a frowny face (maximum value)

alslo @divinitive was right

Find the vertex,

-b/2a

Then plug that into the original equation for the. Mix or max if a is positive it's a min
If a is negative it's a max