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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _get_f2rx(self, C, r_x, r_1, r_2):
 """ Defines the f2 scaling coefficient defined in equation 10 """

        drx = (r_x - r_1) / (r_2 - r_1)
        return self.CONSTS["h4"] + (C["h5"] * drx) + (C["h6"] * (drx ** 2.))