Question

Tìm x,y € Z biết [x-5]+[y-3] bé hơn hoặc bằng 0

Answer 1

\(\left|x-5\right|+\left|y-3\right|\le0\)

Mà \(\left\{{}\begin{matrix}\left|x-5\right|\ge0\\\left|y-3\right|\ge0\end{matrix}\right.\)

\(\Leftrightarrow\left|x-5\right|+\left|y-3\right|\ge0\)

Mà \(\left|x-5\right|+\left|y-3\right|\le0\)

\(\Leftrightarrow\left|x-5\right|+\left|y-3\right|=0\)

Mà \(\left\{{}\begin{matrix}\left|x+5\right|\ge0\\\left|y-3\right|\ge0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}\left|x+5\right|=0\\\left|y-3\right|=0\end{matrix}\right.\)

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

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