If f(x) is an even function and (6, 8) is one the points on the graph of f(x), which reason explains why (–6, 8) must also be a point on the graph? Since the function is even, the outputs of a negative x-value and a positive x-value are the same. Since the function is even, the outputs of a negative y-value and a positive y-value are the same. The graph has rotational symmetry, so the point will be reflected across the y-axis. The graph has rotational symmetry, so the point will be rotated 90 degrees about the origin.