4a-(a+6)=-24

$$\underset{\,\,\,\,{\textcolor[rgb]{0.66,0.66,0.66}{\rightarrow {\mathtt{a}}}}}{{solve}}{\left(\begin{array}{l}{\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{a}}{\mathtt{\,-\,}}\left({\mathtt{a}}{\mathtt{\,\small\textbf+\,}}{\mathtt{6}}\right)=-{\mathtt{24}}\\
{\mathtt{4}}{\mathtt{\,\times\,}}{\mathtt{a}}{\mathtt{\,-\,}}{\mathtt{a}}{\mathtt{\,-\,}}{\mathtt{6}}=-{\mathtt{24}}\\
{\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{a}}{\mathtt{\,-\,}}{\mathtt{6}}=-{\mathtt{24}}\\
{\mathtt{3}}{\mathtt{\,\times\,}}{\mathtt{a}}=-{\mathtt{18}}\\
{\mathtt{a}}=-{\mathtt{6}}\end{array}\right)}$$

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