Question

How do you graph `x^2+y^2=9` and what are its lines of symmetry?

Answer 1

This is the standard form for the graph of a circle! `(x-h)^2+(y-k)^2=r^2`
Doesn't a circle have infinitely many lines of symmetry?

Explanation:

Let's look at the graph... its center will be at (0,0), and the radius = 3.

Imagine any line drawn through the center will "split" the circle in half, and can be called a line of symmetry.