SOLUTION: use the quadratic function (((f(x)=-2/5(x+2)^2-3))) to answer the following: A)Find the vertex B)What is the axis of symmetry? C)How does the graph open(up or down)? Th

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons  -> Quadratic Equation Lesson -> SOLUTION: use the quadratic function (((f(x)=-2/5(x+2)^2-3))) to answer the following: A)Find the vertex B)What is the axis of symmetry? C)How does the graph open(up or down)? Th      Log On


   

Question 87932: use the quadratic function (((f(x)=-2/5(x+2)^2-3))) to answer the following:
A)Find the vertex
B)What is the axis of symmetry?
C)How does the graph open(up or down)?
Thanks you for any help you can provide. what i have so far is the formula which i believe is correct: (-b/2a,f(-b/2a)). I also have a=-2/5 b=(x+2)^2 but I'm not positive just because its a fraction, I'm unsure. well thanks for your help!
Answer by Nate(3500) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+%28-2%2F5%29%28x+%2B+2%29%5E2+-+3
This is in quadratic form: f%28x%29+=+a%28x+-+h%29%5E2+%2B+k
* "a" determines if the parabola opens up or down
~> positive "a" means up
~> negative "a" means down
* "h" and "k" determines the vertex
Vertex (h,k)
f%28x%29+=+%28-2%2F5%29%28x+%2B+2%29%5E2+-+3
a = -2/5
h = -2
k = -3
Vertex: (-2,-3)
Opens downward
The axis of symmetry is x+=+-2 since the parabola is vertical.
graph%28300%2C300%2C-6%2C1%2C-8%2C1%2C%28-2%2F5%29%28x+%2B+2%29%5E2+-+3%29