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For positive (p,q), [ \fracy^2x^2+xy+y^2 \ge \frac2yx+y - 1 ] is not standard; better use known lemma: [ \fracy^2x^2+xy+y^2 \ge \frac2y^2(x+y)^2 + y^2 \dots ] But simplest: Use Nesbitt‑type cyclic sum. If you want to start with, search for:
\textbfSolution. ...