\(P=\left(3x-y\right)^2+\left(y-2020\right)^{600}\)
+Có: \(\left(3x-y\right)^2\ge0với\forall x\)
\(\left(y-2020\right)^{600}\ge0với\forall x\)
\(\Rightarrow\left(3x-y\right)^2+\left(y-2020\right)^{600}\ge0\\ \Leftrightarrow P\ge0\)
+Dấu "=" xảy ra khi \(\left(y-2020\right)^{600}=0\Leftrightarrow y=2020\); \(\left(3x-2020\right)^2=0\Leftrightarrow x=\frac{2020}{3}\)
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