Question

tìm x \(\frac{x-1}{x+1}\ge0\)

Answer 1

ĐKXĐ : \(x\ne-1\)

\(\frac{x-1}{x+1}\ge0\\ \Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-1\ge0\\x+1\ge0\end{matrix}\right.\\\left\{{}\begin{matrix}x-1\le0\\x+1\le0\end{matrix}\right.\end{matrix}\right.\\\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x\ge1\\x\ge-1\end{matrix}\right.\\\left\{{}\begin{matrix}x\le1\\x\le-1\end{matrix}\right.\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x\ge1\\x\le-1\end{matrix}\right.\)