\(\left(\frac{1}{3}-2x\right)^{2018}+\left(3y-x\right)^{2020}\le0\)(1)
Vì \(\left(\frac{1}{3}-2x\right)^{2018}\ge0\forall x\); \(\left(3y-x\right)^{2020}\ge0\forall x,y\)
\(\Rightarrow\left(\frac{1}{3}-2x\right)^{2018}+\left(3y-x\right)^{2020}\ge0\forall x,y\)(2)
Từ (1), (2) \(\Rightarrow\left(\frac{1}{3}-2x\right)^{2018}+\left(3y-x\right)^{2020}=0\)
\(\Leftrightarrow\hept{\begin{cases}\frac{1}{3}-2x=0\\3y-x=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=\frac{1}{6}\\y=\frac{1}{18}\end{cases}}\)
\(\Rightarrow\frac{1}{x}+\frac{1}{y}=6+18=24\left(đpcm\right)\)
