a: Khi x=2 thì A=2/2+3=2/5
b \(B=\dfrac{x^2-3x+x+3-x^2+3}{\left(x-3\right)\left(x+3\right)}=\dfrac{-2x+6}{\left(x-3\right)\left(x+3\right)}=\dfrac{-2}{x+3}\)
c: \(C=A+B=\dfrac{x-2}{x+3}=\dfrac{x+3-5}{x+3}=1-\dfrac{5}{x+3}\)
Để C nguyên thì \(x+3\in\left\{1;-1;5;-5\right\}\)
=>\(x\in\left\{-2;-4;2;-8\right\}\)