Question

Tìm x thuộc z

a,(x-3)(x-1)<0           b,(x-1)(x+4)>0

c,(x+1)(x+3)              d,(x-2)(x-1)(x+3)

 

Answer 1

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x-3>0\\x-1< 0\end{matrix}\right.\\\left\{{}\begin{matrix}x-3< 0\\x-1>0\end{matrix}\right.\end{matrix}\right.\Leftrightarrow1< x< 3\)

Answer 2

Tham Khảo :

Answer 3

Answer 4

\(a,\Leftrightarrow1< x< 3\Leftrightarrow x=2\\ b,\Leftrightarrow\left[{}\begin{matrix}x< -4\\x>1\end{matrix}\right.\Leftrightarrow x\in\left\{...;-5;-4;2;3;....\right\}\)

Answer 5

\(=>\left\{{}\begin{matrix}x-1< 0\\x-3>0\end{matrix}\right.\)hoặc\(\left\{{}\begin{matrix}x-1>0\\x-3< 0\end{matrix}\right.\)

\(=>\left\{{}\begin{matrix}x< 1\\x>3\end{matrix}\right.\)(loại) hoặc\(\left\{{}\begin{matrix}x>1\\x< 3\end{matrix}\right.\)

\(=>1< x< 3\)

vậy \(1< x< 3\)