Symmetrical functions can be about the x and y axis. Essentially, if we reflect the graph across the y or x axis, we get the same graph. Some other graphs can be reflected across both the x and y axis at the same time and be symmetrical. These can be classified as odd and even functions. You can test this by replacing x and y with -x and -y and simplify the equation. If the results comes out to be the same as the original, it is symmetrical across the origin.
