Ta co : \(\left|x+25\right|\ge0\forall x\in Z\)
\(\left|-y+5\right|\ge0\forall x\in Z\)
Mà : |x + 25| + |-y + 5| = 0
Nên : \(\hept{\begin{cases}\left|x+25\right|=0\\\left|-y+5\right|=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x+25=0\\-y+5=0\end{cases}}\)
\(\Leftrightarrow\hept{\begin{cases}x=-25\\y=5\end{cases}}\)
Ta co : $\left|x+25\right|\ge0\forall x\in Z$|x+25|≥0∀x∈Z
$\left|-y+5\right|\ge0\forall x\in Z$|−y+5|≥0∀x∈Z
Mà : |x + 25| + |-y + 5| = 0
Nên : $$
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