\(a,\frac{x-3}{x+4}=\frac{x+4-7}{x+4}=1-\frac{7}{x+4}\\ \Rightarrow x+4\inƯ\left(7\right)=\left\{-1;-7;1;7\right\}\)
\(b,\frac{3x-15}{x-4}=\frac{3x-12-3}{x-4}=3-\frac{3}{x-4}\\ \Rightarrow x-4\inƯ\left(3\right)=\left\{-1;1;-3;3\right\}\)
\(c,\frac{2x+11}{x+3}=\frac{2x+6+5}{x+3}=2+\frac{5}{x+3}\\ \Rightarrow x+3\inƯ\left(5\right)=\left\{-1;5;-5;1\right\}\)
\(d,\frac{x+5}{x-2}=\frac{x-2+7}{x-2}=1+\frac{7}{x-2}\\ \Rightarrow x-2\inƯ\left(7\right)=\left\{-1;-7;1;7\right\}\)