\(\left(7y-x\right)^{2020}\ge0,\left|5-11x\right|^{2021}\ge0\)
Mà \(\left(7y-x\right)^{2020}+\left|5-11x\right|^{2021}=0\\ \Rightarrow\left\{{}\begin{matrix}\left(7y-x\right)^{2020}=0\\\left|5-11x\right|^{2021}=0\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}7y-x=0\\5-11x=0\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}7y-\dfrac{5}{11}=0\\x=\dfrac{5}{11}\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{5}{77}\\x=\dfrac{5}{11}\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(7y-x\right)^{2020}=0\\\left|5-11x\right|^{2021}=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}7y-x=0\\5-11x=0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}7y=x\\x=\dfrac{5}{11}\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{5}{11}\\y=\dfrac{5}{77}\end{matrix}\right.\)
