SOLUTION: What would the vertex of this equation be f(x) = x2+10x+9 ??

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Question 423658: What would the vertex of this equation be f(x) = x2+10x+9 ??
Answer by tutorcecilia(2152) About Me  (Show Source):
You can put this solution on YOUR website!
The formula for the x-variable of the vertex is %28-%28b%2F2a%29%29
.
f(x) = x2+10x+9
So identify the a, b, and c coeficients:
a= +1; b = +10; and c=+9
.
Plug-in the variables and solve for the x-value:
%28-%2810%2F2%281%29%29%29
x= -5
.
Plug-in x=-5 and solve for the y-variable
.
%28%28-5%29%5E2%2B10%28-5%29%2B9%29
=25-50+9
y = -16
.
so the vertex is (-5, -16)