ta có \(\left(2.a+7\right)⋮\left(2.a+1\right)\)
\(\Rightarrow\left(2.a+1+6\right)⋮\left(2.a+1\right)\)
do \(\left(2.a+1\right)⋮\left(2.a+1\right)\)nên \(6⋮\left(2.a+1\right)\)
\(\Rightarrow\left(2.a+1\right)\inƯ\left(6\right)=\left\{-1;-2;-3;-6;1;2;3;6\right\}\)
rồi bạn kẻ bảng là xong