SOLUTION: Without graphing, determine whether the following paraholas opens upward or downward and find the vertex. I know it opens downward and the vertex is (-1,8) I just don't know how

Algebra ->  Graphs -> SOLUTION: Without graphing, determine whether the following paraholas opens upward or downward and find the vertex. I know it opens downward and the vertex is (-1,8) I just don't know how      Log On


   

Question 328147: Without graphing, determine whether the following paraholas opens upward or downward and find the vertex.
I know it opens downward and the vertex is (-1,8) I just don't know how it was found. Can you please help.
Thanks
Answer by solver91311(24713) About Me  (Show Source):
You can put this solution on YOUR website!


You didn't bother to share the function, but there are a few things that I can share that might help anyway.

For any quadratic polynomial function of the form:



If the graph opens upward, that is, the vertex is a minimum. If the graph opens downward.

The -coordinate of the vertex is given by , and the -coordinate of the vertex is given by

So from what you have told me:



The -coordinate of the vertex is:



The -coordinate of the vertex is:



John