\(\left(x-2018\right)^2=4\)
\(\Leftrightarrow\left(x-2018\right)^2=2^2=\left(-2\right)^2\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2018=2\\x-2018=-2\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2020\\x=2016\end{matrix}\right.\)
Vậy ...
(x-2018)2=4
Mà\(\left[{}\begin{matrix}4=2\\4=-2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}\left(x-2018\right)^2=2^2\\\left(x-2018\right)^2=\left(-2\right)^2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x-2018=2\\x-2018=-2\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2018+2\\x=2018+\left(-2\right)\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2020\\x=2016\end{matrix}\right.\)
Vậy \(x\in\left\{2020;2016\right\}\)
