SOLUTION: f(x)=1/2(x+9)^2+7 I got 95/2 but I am confused because I have never run into a problem with no x-intercept. So how do I write an ordered pair for the vertex?

Algebra ->  Equations -> SOLUTION: f(x)=1/2(x+9)^2+7 I got 95/2 but I am confused because I have never run into a problem with no x-intercept. So how do I write an ordered pair for the vertex?      Log On


   



Question 625231: f(x)=1/2(x+9)^2+7
I got 95/2 but I am confused because I have never run into a problem with no x-intercept. So how do I write an ordered pair for the vertex?

Found 2 solutions by KMST, Alan3354:
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=%281%2F2%29%28x%2B9%29%5E2%2B7+ is a quadratic function.
As such, its graph is a parabola.
Unlike linear functions, which graph as straight lines, quadratic functions are allowed to have no x-intercept.
They may approach the x-axis for a while, but then they change their mind and turn away from the x-axis, never crossing it.

For your function:
f%28x%29=7 for x=-9
For any other value of x,
%28x%2B9%29%5E2%3E0 and f%28x%29%3E7
There is no x-intercept, because f%28x%29%3E=7 for all values of x.
The graph never crosses the x-axis (the y=0 line), because f%28x%29 is never zero.
The function has a minimum at x=-9 with f%28-9%29=7
The vertex of the parabola is at that point: point(-9,7).
Your function graphs as this:
graph%28300%2C300%2C-18%2C2%2C-5%2C45%2C%28x%2B9%29%5E2%2F2%2B7%29

Quadratic functions can be written in the form
f%28x%29=a%28x-h%29%5E2%2Bk or y=a%28x-h%29%5E2%2Bk
with a, h , and k being some real numbers (and a must not be zero).
When written in that form, (h,k) is the vertex, and a tells you how curvy the curve is and which way it goes.
The larger the absolute value of a, the curvier the curve is.
If a is positive, the curve goes up from the vertex on both sides, as %28x-h%29%5E2 gets larger and larger. It looks like a smiley mouth.
If a is negative, the curve goes down from the vertex on both sides, as %28x-h%29%5E2 gets larger and larger. It's frowning.
Your curve is smiling at you.

Answer by Alan3354(69443) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=1/2(x+9)^2+7
I got 95/2 but I am confused because I have never run into a problem with no x-intercept. So how do I write an ordered pair for the vertex?
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The vertex is (-9,7)
95/2 for what?