SOLUTION: I neeed help graphing f(x)=x^2+ 7x-8 I need to understand how to find the vertex, x-intercept,line of symmetry, and the opening of the graph.

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Question 1128358: I neeed help graphing f(x)=x^2+
7x-8 I need to understand how to find the vertex, x-intercept,line of symmetry, and the opening of the graph.
Found 3 solutions by josgarithmetic, MathTherapy, ikleyn:
Answer by josgarithmetic(39620) About Me  (Show Source):
You can put this solution on YOUR website!
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I neeed help graphing f(x)=x^2+
7x-8 I need to understand how to find the vertex, x-intercept,line of symmetry, and the opening of the graph.
----


f%28x%29=x%5E2%2B7x-8

Function f is factorable.
f%28x%29=%28x%2B8%29%28x-1%29

The vertex and symmetry axis both are in the exact middle of the zeros of f.
Symmetry axis x=-3%261%2F2

f%28-3%261%2F2%29=%28-3%261%2F2%2B8%29%28-3%261%2F2-1%29
-20%261%2F4

vertex, ( -3.5, -20.25 )


graph%28400%2C400%2C-20%2C20%2C-20%2C20%2Cx%5E2%2B7x-8%29

Answer by MathTherapy(10555) About Me  (Show Source):
You can put this solution on YOUR website!

I neeed help graphing f(x)=x^2+
7x-8 I need to understand how to find the vertex, x-intercept,line of symmetry, and the opening of the graph.
Unless you want to ALWAYS be WRONG, go along with this person. 

Again, just pretend as though no-one responded to your math question should this person respond to your question.

BTW: The graph opens UPWARD since "a" is > 0 (positive)



IGNORE all below as it's all RUBBISH:

Symmetry axis cross%28x=-4%261%2F2%29





cross%28f%28-4%261%2F2%29=%28-4%261%2F2%2B8%29%28-4%261%2F2-1%29%29

cross%28-19%261%2F4%29





Vertex,  (  -4.5, -19.25 ){{graph(400,400,-20,20,-20,20,x^2+7x-8)}}}

Answer by ikleyn(52810) About Me  (Show Source):
You can put this solution on YOUR website!
.
If you want to learn these issues,  read the lessons
    - HOW TO complete the square to find the minimum/maximum of a quadratic function
    - Briefly on finding the minimum/maximum of a quadratic function
    - HOW TO complete the square to find the vertex of a parabola
    - Briefly on finding the vertex of a parabola
in this site.

Also,  you have this free of charge online textbook in ALGEBRA-I in this site
    - ALGEBRA-I - YOUR ONLINE TEXTBOOK.

The referred lessons are the part of this textbook under the topic "Finding minimum/maximum of quadratic functions".


Save the link to this online textbook together with its description

Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson

to your archive and use it when it is needed.


Also, on completing the squares you have the lesson
    - HOW TO complete the square - Learning by examples
in this site.

It is in the same textbook under the topic  "Quadratic equations".


                    H a p p y   l e a r n i n g  ! !