\(\left(x^2+4x+7\right)\) \(⋮\) \(\left(x+4\right)\)
\(\Rightarrow\) \(\left(x.x+4x+7\right)\) \(⋮\) \(\left(x+4\right)\)
\(\Rightarrow\) \(x\left(x+4\right)+7\) \(⋮\) \(\left(x+4\right)\)
\(\Rightarrow\) \(7⋮\left(x+4\right)\) \(\Rightarrow\) \(\left(x+4\right)\inƯ\left(7\right)\) \(=\left\{\pm1;\pm7\right\}\)
\(\Rightarrow\) \(x\in\left\{-11;-5;-3;3\right\}\)