Question

Tìm x để A < -1 biết A = \(\dfrac{x}{x+1}\)

Answer 1

\(\dfrac{x}{x+1}< -1\)

\(\Leftrightarrow\dfrac{x}{x+1}+1< 0\)

\(\Leftrightarrow\dfrac{x+x+1}{x+1}< 0\)

\(\Leftrightarrow2x+1< 0\)

\(\Leftrightarrow2x< -1\)

\(\Leftrightarrow x< -\dfrac{1}{2}\)

Vậy \(x< -\dfrac{1}{2}\) thì \(A< -1\)