SOLUTION: what is the axis of symetry if the equation is two x squared plus twelve x plus nine?

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Question 303150: what is the axis of symetry if the equation is two x squared plus twelve x plus nine?
Found 2 solutions by Fombitz, stanbon:
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
f%28x%29=2x%5E2%2B12x%2B9
Complete the square to put the equation into vertex form.
g%28x%29=a%28x-h%29%5E2%2Bk where the vertex is (h,k)
The vertex lies on the axis of symmtery.
f%28x%29=2%28x%5E2%2B6x%29%2B9
f%28x%29=2%28x%5E2%2B6x%2B9%29%2B9-18
f%28x%29=2%28x%2B3%29%5E2-9
The axis of symmetry is x=-3.
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Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
what is the axis of symmetry if the equation is two x squared plus twelve x plus nine?
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y = 2x^2+12x+9
a = 2 ; b = 12 ; c = 9
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The axis of symmetry occurs where x = -b/2a
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x = -12/(2*2) = -3
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graph%28400%2C300%2C-10%2C10%2C-10%2C20%2C2x%5E2%2B12x%2B9%29
Cheers,
Stan H.