Ta có: \(\left\{{}\begin{matrix}n-p=1\\n=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=9\\n=10\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}p=z=9\\n=10\end{matrix}\right.\)
\(\Rightarrow A=z+n=9+10=19\left(u\right)\)
\(KHNT:^{19}_9F\)