What is the line of symmetry of the parabola y=x2+6x-9?

x=6
x=-9
x=-3

In the given parabola    the line of symmetry is the axis x  = -3

Step-by-step explanation:

Here, the given equation of the parabola is :

Now, in the Standard Form of the Parabolic Equation: ,

The axis of symmetry is a vertical line x  = −b / 2 a .

Now, here comparing the given parabolic equation with teh standard form, we get  :  

a  = 1 , b = 6 and c  = -9

So, the axis of symmetry =  

Hence, here in the given parabola    the line of symmetry is the axis x  = -3.

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