Which is a possible turning point for the continuous function f(x)?

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For the given coordinates we can see that (–2, 0) and (4, 0) coordinates are in a same line, that is on the x-axis. But the coordinate (0, –2) is the lowest point on the graph. Therefore, (0, –2) is the turning point for the continuous function given

These are the multiples of 15 but what you are probably asking or what are the factors of 15