\(\left\{{}\begin{matrix}2x+3y+x-3y=13+2\\x-3y=2\end{matrix}\right.\) (=)\(\left\{{}\begin{matrix}3x=15\\x-3y=2\end{matrix}\right.\)
(=)\(\left\{{}\begin{matrix}x=5\\5-3y=2\end{matrix}\right.\)(=)\(\left\{{}\begin{matrix}x=5\\y=1\end{matrix}\right.\)
vậy hệ phương trình có tập nghiêm là s=\(\left\{5;1\right\}\)
\(\left\{{}\begin{matrix}2x+3y=13\\x-3y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}3x=15\\x-3y=2\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{15}{3}=5\\x-3y=2\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=5\\5-3y=2\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}x=5\\3y=3\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=5\\y=1\end{matrix}\right.\\ Vậy:\left(x;y\right)=\left(5;1\right)\)
