Chapter 1 - Graphs - 1.2 Graphs of Equations in Two Variables; Intercepts; Symmetry - 1.2 Assess Your Understanding - Page 19: 90

For x-axis reflection symmetry, f(x,y) = f(x,-y) For y-axis reflection symmetry, f(x,y) = f(-x,y) For symmetry about the origin, f(x,y) = f(-x,-y) If you reflect about both the x and y-axis, it is equivalent to reflecting about the origin. If you reflect about the origin and then one axis, you have reflected about the other axis.

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