Question

giải hệ 2x-y=5 và x+3y=1

Answer 1

x=\(\dfrac{16}{7}\)    y=\(\dfrac{-3}{7}\)

Answer 2

\(\left\{{}\begin{matrix}2x-y=5\\x+3y=1\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}2x-y=5\\-2x-6y=-2\end{matrix}\right.\)

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

\(\Leftrightarrow\left\{{}\begin{matrix}x=1+\dfrac{\left(-3\right).\left(-3\right)}{7}\\y=-\dfrac{3}{7}\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=\dfrac{16}{7}\\y=-\dfrac{3}{7}\end{matrix}\right.\)