a. \(x=\dfrac{a+2}{a+1}=\dfrac{a+1+1}{a+1}=1+\dfrac{1}{a+1}\) nguyên khi :
\(\left(a+1\right)\inƯ\left(1\right)=\left\{1;-1\right\}\)
\(\Rightarrow a=\left\{0;-2\right\}\)
b. \(x=\dfrac{a+5}{a+3}=\dfrac{a+3+2}{a+3}=1+\dfrac{2}{a+1}\) nguyên khi :
\(\left(a+1\right)\inƯ\left(2\right)=\left\{1;-1;2;-2\right\}\)
\(\Rightarrow a=\left\{0;-2;1;-3\right\}\)
c. \(x=\dfrac{a-4}{a-2}=\dfrac{a-2-2}{a-2}=1-\dfrac{2}{a-2}\) nguyên khi :
\(\left(a-2\right)\inƯ\left(2\right)=\left\{1;-1;2;-2\right\}\)
\(\Rightarrow a=\left\{3;1;4;0\right\}\)
d. \(x=\dfrac{a-1}{a-2}=\dfrac{a-2+1}{a-2}=1+\dfrac{1}{a-2}\) nguyên khi :
\(\left(a-2\right)\inƯ\left(1\right)=\left\{1;-1\right\}\)
\(\Rightarrow a=\left\{3;1\right\}\)
