We have the next function
![f(x)=x^2-5](https://img.qammunity.org/2023/formulas/mathematics/college/kfmuotgq4oeqvaltunjsmkr668zs5pj80x.png)
In order to sketch the graph, we can calculate some points
x f(x)
-5 20
-2 -1
0 -5
2 -1
5 20
The sketch is
As we can see the vertex is (0,-5), and the equation of the axis of symmetry is x=0 the axis of symmetry is the line in blue