$${\mathtt{9}}{\mathtt{\,\times\,}}{\mathtt{k}}{\mathtt{\,-\,}}{\mathtt{4}} = {\mathtt{6}}{\mathtt{\,\times\,}}{\mathtt{9}}{\mathtt{\,\small\textbf+\,}}{\mathtt{k}} \Rightarrow {\mathtt{k}} = {\frac{{\mathtt{29}}}{{\mathtt{4}}}} \Rightarrow {\mathtt{k}} = {\mathtt{7.25}}$$
.
) 
