$$\underset{\,\,\,\,{\textcolor[rgb]{0.66,0.66,0.66}{\rightarrow {\mathtt{vater, sohn, mutter, tochter}}}}}{{solve}}{\left(\begin{array}{l}{\mathtt{vater}}={\mathtt{1.4}}{\mathtt{\,\times\,}}{\mathtt{sohn}}\\
{\mathtt{mutter}}={\frac{{\mathtt{sohn}}}{{\mathtt{2}}}}\\
{\mathtt{tochter}}={\frac{{\mathtt{mutter}}{\mathtt{\,\times\,}}{\mathtt{2}}}{{\mathtt{3}}}}\\
{\mathtt{vater}}{\mathtt{\,\small\textbf+\,}}{\mathtt{sohn}}{\mathtt{\,\small\textbf+\,}}{\mathtt{mutter}}{\mathtt{\,\small\textbf+\,}}{\mathtt{tochter}}={\mathtt{9\,700}}\end{array}\right)} \Rightarrow \left\{ \begin{array}{l}{\mathtt{vater}} = {\mathtt{4\,200}}\\
{\mathtt{sohn}} = {\mathtt{3\,000}}\\
{\mathtt{mutter}} = {\mathtt{1\,500}}\\
{\mathtt{tochter}} = {\mathtt{1\,000}}\\
\end{array} \right\}$$
.