Question

(7x+4y=1 phần 3x-2y=9 giúp mk vs ak

Answer 1

\(\left\{{}\begin{matrix}7x+4y=1\\3x-2y=9\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}7x+4y=1\\6x-4y=18\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}7x+4y+6x-4y=1+18\\3x-2y=9\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}13x=19\\2y=3x-9\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{19}{13}\\y=\dfrac{3}{2}x-\dfrac{9}{2}=\dfrac{3}{2}\cdot\dfrac{19}{13}-\dfrac{9}{2}=\dfrac{57}{26}-\dfrac{9}{2}=-\dfrac{30}{13}\end{matrix}\right.\)