Question

\(\left\{{}\begin{matrix}\frac{x}{3}+\frac{y}{4}-2=0\\5x-y=11\end{matrix}\right.\)

giải hpt

Answer 1

\(\left\{{}\begin{matrix}\frac{x}{3}+\frac{y}{4}-2=0\\5x-y=11\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\frac{12x}{3}+\frac{12y}{4}=24\\5x-y=11\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x+3y=24\\5x-y=11\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x+3y=24\\15x-3y=33\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}4x+3y=24\\19x=57\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\15-y=11\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=4\end{matrix}\right.\)

Answer 2

\(\left\{{}\begin{matrix}\frac{x}{3}+\frac{y}{4}-2=0\\5x-y=11\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}4x+3y=24\\5x-y=11\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}4x+3y=24\\15x-3y=33\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}19x=57\\5x-y=11\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x=3\\y=4\end{matrix}\right.\)

vậy hệ phương trình có nghiệm (x;y)=(3;4)