Ta có: \(\left\{{}\begin{matrix}p+e+n=60\\p=e\\p=n\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=e=20\\n=20\end{matrix}\right.\)
⇒ Y là canxi (Ca)
\(\left\{{}\begin{matrix}P+E+N=60\\P=E\\P=N\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}P+E+N=60\\P=E=N\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}P=E=Z=20\\N=20\end{matrix}\right.\left(Đề.hỏi.gì.á.em?\right)\)