SOLUTION: How do you find the vertex, axis of symmetry and graph: f(x) -x^2-6x+3, in the back of my math book it says the vertex is (-3,12) i keep getting (-3,-6) Thanx :)

Question 145727: How do you find the vertex, axis of symmetry and graph: f(x) -x^2-6x+3, in the back of my math book it says the vertex is (-3,12) i keep getting (-3,-6) Thanx :)
Found 3 solutions by stanbon, jim_thompson5910, Earlsdon:
Answer by stanbon(75887)   (Show Source): You can put this solution on YOUR website!
find the vertex, axis of symmetry and graph: f(x)= -x^2-6x+3, in the back of my math book it says the vertex is (-3,12) i keep getting (-3,-6)
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Vertex occurs where x = -b/2a = 6/-2 = -3
f(-3) = -(-3)^2-6(-3)+3 = -9+18+3 = 12
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Vertex at (-3,12)
Axis at x = -3
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Cheers,
Stan H.

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
Start with the given function

Plug in (which is the x-coordinate of the vertex)

Raise -3 to the 2nd power to get 9

Multiply 6 and -3 to get -18

Rewrite as

Add -9 and 18 to get 9

Add 9 and 3 to get 12

So when , we have

This means that the vertex is (-3,12)

Answer by Earlsdon(6294)   (Show Source): You can put this solution on YOUR website!
Find the vertex and axis of symmetry:

The equation of the axis of symmetry is:

Substitute this into the given function to find the vertex location.

The vertex is at: (-3, 12)

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