# What is the axis of symmetry and vertex for the graph y= 2x ^2 -9?

Apr 22, 2016

Axis of symmetry $\to x = 0$
Vertex$\to \left(x , y\right) = \left(0 , 9\right)$

#### Explanation:

Compare to the standard form:$\text{ } y = a {x}^{2} + b x + c$

There is no $b x$ term so the function is symmetric about the y-axis

If the equation had been $y = 2 {x}^{2}$ then the vertex would have been at $\left(0 , 0\right)$. However, the $- 9$ lowers the graph by 9 so the vertex is at:

Vertex$\to \left(x , y\right) = \left(0 , - 9\right)$