a: Để 2x-3/x-2 là số nguyên thì \(2x-4+1⋮x-2\)
\(\Leftrightarrow x-2\in\left\{1;-1\right\}\)
hay \(x\in\left\{3;1\right\}\)
b: \(A=\dfrac{2x+1}{x+3}-\dfrac{x-5}{x+3}=\dfrac{2x+1-x+5}{x+3}=\dfrac{x+6}{x+3}\)
Để A là số nguyên thì \(x+3+3⋮x+3\)
\(\Leftrightarrow x+3\in\left\{1;-1;3;-3\right\}\)
hay \(x\in\left\{-2;-4;0;-6\right\}\)