Question

Tìm x để A= x-2/3x+2

a) A=0 b) A<0

Answer 1

\(A=\dfrac{x-2}{3x+2}\)

ĐKXĐ: \(x\ne-\dfrac{2}{3}\)

a, \(A=\dfrac{x-2}{3x+2}=0\)

\(\Rightarrow x-2=0\Rightarrow x=2\)

\(b,A=\dfrac{x-2}{3x+2}< 0\)

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

\(\Rightarrow-\dfrac{2}{3}< x< 2\)