Find all pairs of integers (x,y) that satisfy the following equality: ∣x+∣x+∣x∣∣⋅∣∣−y∣−y∣−y∣=2011.
Solution
Since 2011 is a prime number, every multiple of the left-hand side must be equal to either 1 or 2011. If x≥0, the first multiple equals 3x, and there are no solutions. Similarly, there are no solutions if y≤0 (the second multiple is −3y). Suppose now that x<0 and y>0. Then ∣x+∣x+∣x∣∣⋅∣∣−y∣−y∣−y∣=∣x+∣x−x∣∣⋅∣∣y−y∣−y∣=∣x∣⋅∣−y∣=−xy=−2011. Recalling that 2011 is prime, we get the above answers.
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Source: MathNet,
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