The graph of a quadratic function touches, but does not cross, the x-axis at x = 4. Which function represents this situation?

If a quadratic touches the x-axis at x = 4 without crossing it, x = 4 is a repeated root. The function must therefore include the factor (x − 4)², which expands to x² − 8x + 16. Choice C, y = x² − 8x + 16, represents this situation.

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