Question

-2x^(2)+2*(m-2)*x+m-2  tìm m để f(x) < 0 

Answer 1

gõ latex đc hơm, ghi vậy k hỉu j lun 

Answer 2

\(-2x^2+2\left(m-2\right)x+m-2< 0\) 

\(\Leftrightarrow\) \(x^2+\left(2-m\right)x+\dfrac{2-m}{2}>0\)

\(\Leftrightarrow\) \(\left\{{}\begin{matrix}\Delta< 0\\a>0\end{matrix}\right.\) \(\Leftrightarrow\) \(\left\{{}\begin{matrix}\left(2-m\right)^2-2\left(2-m\right)< 0\\a=1>0\end{matrix}\right.\) \(\Leftrightarrow\) \(m^2-2m< 0\) \(\Leftrightarrow\)\(0< m< 2\)

 

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