Question

Tìm x

(x-2).(x+ \(\dfrac{2}{3}\)) <0

Answer 1

Ta có :

\(\left(x-2\right)\left(x+\dfrac{2}{3}\right)< 0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-2< 0\\x+\dfrac{2}{3}>0\end{matrix}\right.\\\left\{{}\begin{matrix}x-2>0\\x+\dfrac{2}{3}< 0\end{matrix}\right.\end{matrix}\right.\)

+) Với \(\left\{{}\begin{matrix}x-2< 0\\x+\dfrac{2}{3}>0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x< 2\\x>\dfrac{-2}{3}\end{matrix}\right.\)

+) Với \(\left\{{}\begin{matrix}x-2>0\\x+\dfrac{2}{3}< 0\end{matrix}\right.\) \(\Leftrightarrow\left\{{}\begin{matrix}x>2\\x< -\dfrac{2}{3}\end{matrix}\right.\)

Vậy ..