Let be the solutions to the equation . Then can be written as , where is a square-free positive integer, and are positive integers with . Compute .
Solution
Note that is clearly not a solution, so we can divide the equation by to get . Letting , we get that , so . Since has absolute value less than 2, the associated are on the unit circle, and thus the two solutions for in this case each have magnitude 1. For , the roots are negative reals that are reciprocals of each other. Thus, the sum of their absolute values is the absolute value of their sum, which is . Thus, the sum of the magnitudes of the four solutions are .
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