Question

Giải hệ pt: \(\left\{{}\begin{matrix}-18x-14y=-25\\66x-66y=33\end{matrix}\right.\)

Answer 1

\(\left\{{}\begin{matrix}-18x-14y=-25\\66x-66y=33\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}18x+14y=25\\2x-2y=1\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}18x+14y=25\\18x-18y=9\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}32y=16\\2x-2y=1\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{16}{32}=\dfrac{1}{2}\\2x-1=1\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{1}{2}\\2x=2\end{matrix}\right.\\ \Leftrightarrow\left\{{}\begin{matrix}y=\dfrac{1}{2}\\x=1\end{matrix}\right.\)

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