Question

(x + 1) . (x - 2) < 0

Answer 1

Ta có: `x - 2 < x + 1`

Do `(x+1)(x-2) < 0`

`=>` \(\left[{}\begin{matrix}x-2>0\\x+1< 0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x>2\\x< -1\end{matrix}\right.\)

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