set p to zz * ((((0.002967721961 * zz - 0.563424278001) * zz + 6.968710824105) * zz - 25.569010496528) * zz + 28.536655482611) / ((((zz - 21.947795316429) * zz + 147.065635402681) * zz - 383.877095760369) * zz + 342.439865791308)