# What is the axis of symmetry of the graph of y=-(x+3)^2-6?

May 26, 2015

If you complete the square, as was done in this case, it's not hard.
It's also easy to find the vertex.

$\left(x + 3\right)$ means that the parabola is displaced $3$ to the left as compared to the standard-parabola $y = {x}^{2}$
(because $x = - 3$ would make $\left(x + 3\right) = 0$)

[It is also displaced $6$ down, and the minus in front of the square means it's upside down, but that has no influence on the symmetry-axis, ]

So the axis of symmetry lies at $x = - 3$
And the vertex is $\left(- 3 , - 6\right)$
graph{-(x+3)^2-6 [-16.77, 15.27, -14.97, 1.05]}