SOLUTION: find the equation of the axis of symmetry of the parabola f(x)=3x^2+24x+47

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Question 109696: find the equation of the axis of symmetry of the parabola f(x)=3x^2+24x+47
Found 2 solutions by jim_thompson5910, stanbon:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
To find the axis of symmetry, use this formula:

x=-b%2F%282a%29

From the equation y=3x%5E2%2B24x%2B47 we can see that a=3 and b=24

x=%28-24%29%2F%282%2A3%29 Plug in b=24 and a=3


x=%28-24%29%2F6 Multiply 2 and 3 to get 6



x=-4 Reduce


So the axis of symmetry is x=-4

Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
axis of symmetry of the parabola f(x)=3x^2+24x+47
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Complete the square on the x-terms:
3x^2+24x = y-47
3(x^2+8x+4^2) = y-47+3*4^2
3(x+4)^2 = y+1
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Axis of symmetry: x = -4
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Graph:
graph%28400%2C300%2C-10%2C10%2C-10%2C100%2C3x%5E2%2B24x%2B47%29
Cheers,
Stan H.