Ta có:
\(x+y=\dfrac{x}{2}+\dfrac{x}{2}+\dfrac{y}{3}+\dfrac{y}{3}+\dfrac{y}{3}\ge5\sqrt[5]{\dfrac{x^2y^3}{2^2.3^3}}=5\sqrt[5]{\dfrac{108}{108}}=5\) (đpcm)
Dấu "=" xảy ra khi \(x=2;y=3\)
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