Problem: Find the largest real number x such that 3x+34−x=1.
Solution
Solution: Cubing both sides of the given equation yields x+33x(4−x)(3x+34−x)+4−x=1, which then becomes 4+33x(4−x)=1 or 3x(4−x)=−1. Cubing both sides of this equation gives x(4−x)=−1 or x2−4x=1. This means (x−2)2=5 so x=2±5 and the largest real solution is x=2+5.
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Source: MathNet,
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