Question

Tìm x,y, z nguyên biết lxl+lyl+Lzl=0

Answer 1

Ta có :

\(\left\{{}\begin{matrix}\left|x\right|\ge0\\\left|y\right|\ge0\\\left|z\right|\ge0\end{matrix}\right.\)

\(\Leftrightarrow\left|x\right|+\left|y\right|+\left|z\right|\ge0\)

Mà \(\left|x\right|+\left|y\right|+\left|z\right|=0\)

\(\Leftrightarrow\left\{{}\begin{matrix}\left|x\right|=0\\\left|y\right|=0\\\left|z\right|=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x=0\\y=0\\z=0\end{matrix}\right.\)

Vậy .........