A function being even or odd refers to the symmetry of the graph.
Refer to the graphs attached to this answer.
To test if a function is even or odd, replace x in the function with -x. If the new graph is exactly the same as the old graph, the function is even. If not, multiply the entire function by -1. If the new graph is symmetrical to the y-axis, then the function is odd. If it isn't symmetrical, the function is neither even nor odd.
The first graph is the original function. The second graph is the function with x replaced by -x. The third graph is the function multiplied by -1.
The second graph is not equal to the original function. The third graph is symmetrical to the y-axis.
This function is odd.
