Question

Giải hệ:
a,\(\left\{{}\begin{matrix}3\left(x-y\right)-y=11\\x-2\left(x+5y\right)=-15\end{matrix}\right.\)
b,\(\left\{{}\begin{matrix}\frac{x+y}{3}-\frac{2}{3}=2\\\frac{4x-y}{6}+\frac{x}{4}=1\end{matrix}\right.\)

Answer 1

a/ \(\Leftrightarrow\left\{{}\begin{matrix}3x-4y=11\\-x-10y=-15\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=5\\y=1\end{matrix}\right.\)

b/ \(\Leftrightarrow\left\{{}\begin{matrix}x+y=8\\\frac{2x}{3}+\frac{x}{4}-\frac{y}{6}=1\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x+y=8\\\frac{11}{12}x-\frac{y}{6}=1\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x+y=8\\11x-2y=12\end{matrix}\right.\) \(\Rightarrow\left\{{}\begin{matrix}x=\frac{28}{13}\\y=\frac{76}{13}\end{matrix}\right.\)