Question

giải BTP: `m^2 -2m-3 >0`

Answer 1

\(m^2-2m-3>0\)

=>\(m^2-3m+m-3>0\)

=>\(\left(m-3\right)\left(m+1\right)>0\)

TH1: \(\left\{{}\begin{matrix}m-3>0\\m+1>0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}m>3\\m>-1\end{matrix}\right.\)

=>m>3

TH2: \(\left\{{}\begin{matrix}m-3< 0\\m+1< 0\end{matrix}\right.\)

=>\(\left\{{}\begin{matrix}m< 3\\m< -1\end{matrix}\right.\)

=>m<-1

Answer 2

\(\Leftrightarrow\left(m+1\right)\left(m-3\right)>0\)

\(\Rightarrow\left[{}\begin{matrix}m< -1\\m>3\end{matrix}\right.\)