Question

\(\left\{{}\begin{matrix}108u+63v=7\\81u+84v=7\end{matrix}\right.\)

Answer 1

\(\left\{{}\begin{matrix}108u+63v=7\\81u+84v=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}432u+252v=28\\243u+252v=21\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}89u=7\\81u+84v=7\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}u=\dfrac{7}{89}\\v=\left(7-81.\dfrac{7}{89}\right):84\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}u=\dfrac{7}{89}\\v=\dfrac{2}{267}\end{matrix}\right.\)