Question

giải bpt 

\(x^2-1>0\)

Answer 1

\(x^2-1>0\Rightarrow x^2>1\Rightarrow\left|x\right|>1\Rightarrow\left[{}\begin{matrix}x>1\\x< -1\end{matrix}\right.\)

Answer 2

\(\Rightarrow x^2>1\Rightarrow x>1\) hoặc \(x< -1\)

Answer 3

Ta có: \(x^2-1>0\)

\(\Leftrightarrow\left(x-1\right)\left(x+1\right)>0\)

\(\Leftrightarrow\left[{}\begin{matrix}x>1\\x< -1\end{matrix}\right.\)