Bài 2:
a: \(=\dfrac{-x-1+2x-2-x+5}{\left(x-1\right)\left(x+1\right)}\cdot\dfrac{\left(x-1\right)\left(x+1\right)}{1-2x}\)
\(=\dfrac{2}{1-2x}=\dfrac{-2}{2x-1}\)
b: Để C là số nguyên thì \(2x-1\in\left\{1;-1;2;-2\right\}\)
=>\(x\in\left\{0;\dfrac{3}{2};-\dfrac{1}{2}\right\}\)
Bài 3:
a: \(A=\left(\dfrac{-\left(x-2\right)}{x+3}+\dfrac{x-3}{x+2}+\dfrac{2-x}{\left(x+2\right)\left(x+3\right)}\right):\dfrac{x-1-x}{x-1}\)
\(=\dfrac{-x^2+4+x^2-9+2-x}{\left(x+3\right)\left(x+2\right)}\cdot\dfrac{x-1}{-1}\)
\(=\dfrac{-x+3}{\left(x+3\right)\left(x+2\right)}\cdot\dfrac{1-x}{1}=\dfrac{x-1}{x+2}\)
b: Để A=0 thì x-1=0
=>x=1(loại)
c: Để A>0 thì x-1/x+2>0
=>x>1 hoặc x<-2