The equation for the line of symmetry would be either x = 0 if the figure is symmetric about the y-axis, or y = 0 if it's symmetric about the x-axis.
Without more information, we cannot determine if y = -x or y = x are lines of symmetry for the figure.
The equation that describes a line of symmetry for the figure would depend on the orientation of the figure itself. Based on the principles of symmetry for functions, an even function is symmetric about the y-axis, which is described by the equation x = 0.
In contrast, an odd function exhibits symmetry when reflected about both the y-axis and the x-axis, which is not the case for a single line of symmetry.
Assuming the figure in question possesses symmetry about the y-axis, the correct equation describing the line of symmetry would be x = 0.
If the symmetry is about the x-axis, then the correct equation would be y = 0.
Without additional information about the figure, it is impossible to determine whether the lines y = -x or y = x would act as lines of symmetry.