I've doing some research in wikipedia, where appears this example:$3x^{3} - 5x^2 + 5x - 2 = 0$the rational solution must be among the numbers symbolically indicated by: ±\frac{1,2}{1,3}
So I get that the rational solution must be among ±\frac{2}{3}; but, why it must be among ±\frac{1}{1}?