Ta có:
\(A=\frac{1}{x-1}:\frac{x-2}{2.\left(x-1\right)}\)
\(A=\frac{1}{x-1}.\frac{2.\left(x-1\right)}{x-2}\)
\(A=\frac{2.\left(x-1\right)}{\left(x-1\right).\left(x-2\right)}\)
\(A=\frac{2}{x-2}.\)
Để \(A\in Z\) thì \(2⋮x-2.\)
\(\Rightarrow x-2\inƯC\left(2\right)\)
\(\Rightarrow x-2\in\left\{\pm1;\pm2\right\}.\)
\(\Rightarrow\left[{}\begin{matrix}x-2=1\\x-2=-1\\x-2=2\\x-2=-2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=1+2\\x=\left(-1\right)+2\\x=2+2\\x=\left(-2\right)+2\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=3\\x=1\\x=4\\x=0\end{matrix}\right.\left(TM\right).\)
Vậy \(x\in\left\{3;1;4;0\right\}.\)
Chúc bạn học tốt!
\(A=\frac{1}{x-1}:\frac{x-2}{2\left(x-1\right)}\)
\(A=\frac{1}{x-1}.\frac{2\left(x-1\right)}{x-2}\)
\(A=\frac{2\left(x-1\right)}{\left(x-2\right)\left(x-1\right)}\)
\(A=\frac{2}{x-2}\)
=> x-2 thuộc Ư(2)={-1,-2,1,2}
=> x thuộc {0,1,3,4}