Which function has a vertex on the y-axis?

A parabola’s vertex lies on the y-axis when its x-coordinate is 0. For choice C, f(x) = (x − 2)(x + 2) = x² − 4, which has its vertex at (0, −4). The other choices have vertices with nonzero x-coordinates, so choice C, f(x) = (x − 2)(x + 2), is correct.

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